The Scrum values of courage, openness, and respect are touched in this situation. Courage means that the Scrum Team members have the courage to do the right thing and work on tough problems, and also to speak up when they have concerns or disagreements. Openness means that the Scrum Team members and stakeholders agree to be open about all the work and the challenges with performing the work. Respect means that the Scrum Team members respect each other to be capable, independent people, and also respect the opinions and ideas of others.

In this case, the newest developer showed courage by expressing his feelings during the Sprint Retrospective, which is an opportunity for the Scrum Team to inspect itself and create a plan for improvements. The rest of the Developers should have been more open to listening to his perspective and ideas throughout the Sprint, as they might have valuable insights or suggestions for improving the product or the process. The Developers should also have respected the newest developer as a member of the team, and given him a fair chance to contribute and collaborate with them.

The Scrum Guide, November 2020, p. 13-14

What are the 5 Scrum Values?, Visual Paradigm, accessed on September 30, 2023

Scrum Values Poster, Scrum.org, accessed on September 30, 2023

The best way to determine if the Product Owner is interacting with the Developers enough throughout a Sprint is to observe whether both parties are satisfied with the Increment.The Increment is a concrete stepping stone toward the Product Goal1.It must be usable and meet the Definition of Done1.The Product Owner is accountable for maximizing the value of the product resulting from the work of the Developers1.The Developers are accountable for creating a valuable, useful, and potentially releasable Increment every Sprint1. Therefore, if both the Product Owner and the Developers are happy with the quality and value of the Increment, it means that they have communicated and collaborated effectively throughout the Sprint.

Some reasons why the other options are not correct are:

A: The Developers should determine the percentage of time the Product Owner is required to be present and monitor whether the Product Owner's average presence is around this figure. This option is not correct because it implies that there is a fixed or optimal amount of time that the Product Owner should spend with the Developers, which may not be true. The Product Owner's interaction with the Developers may vary depending on the context, complexity, and uncertainty of the product and the Sprint.The Scrum Guide does not prescribe any specific time or frequency for the Product Owner's involvement with the Developers1.The Product Owner should be available to provide guidance and feedback to the Developers as needed, but not interfere with their self-organization and autonomy1.

B: Check the Daily Scrum reports to see whether the Product Owner was present at the majority of the Daily Scrum meetings. This option is not correct because it assumes that the Daily Scrum is a meeting where the Product Owner should be present, which is not true.The Daily Scrum is an event for and by the Developers12, not for reporting or accountability to anyone else.The Product Owner may attend as an observer or a collaborator, but only if invited by the Developers12. The presence or absence of the Product Owner at the Daily Scrum does not indicate how much they interact with the Developers throughout the Sprint.

C: Observe whether the Developers need to ask the Product Owner questions at times other than during the Daily Scrum. This option is not correct because it implies that asking questions is a sign of insufficient interaction, which may not be true. Asking questions is a natural and healthy part of communication and collaboration between the Product Owner and the Developers. It shows that they are engaged, curious, and willing to learn from each other. It also helps them to clarify requirements, expectations, and feedback, and to resolve any ambiguities or conflicts. Asking questions does not necessarily mean that there is a lack of interaction, but rather that there is a need for more information or clarification.

What is an Increment? | Scrum.org

What Is a Daily Standup? | A Guide to Running Effective Standup Meetings | Atlassian

B: Ask the Developers and the Product Owner if removing regression testing from the Definition of Done allows the team to produce useful and valuable Increments at the end of every Sprint. This is a good way to challenge the decision and make them think about the consequences of lowering the quality standards. The Scrum Master can help them understand the importance of delivering a potentially releasable product increment that meets the expectations of the stakeholders and customers.

C: Ask the Developers and the Product Owner what problem they are going to solve by altering the Definition of Done during the Sprint to remove regression testing. Will this raise transparency or improve quality? This is a good way to explore the root cause of the issue and find out why they are not able to complete regression testing for all of the selected Product Backlog items in the Sprint. The Scrum Master can help them identify and remove any impediments or inefficiencies that prevent them from achieving their Sprint Goal.

Scrum Guide 2020, page 9: ''The Definition of Done is a formal description of the state of the Increment when it meets the quality measures required for the product.''

Scrum Guide 2020, page 13: ''The Scrum Master serves the Scrum Team in several ways, including coaching the team members in self-management and cross-functionality.''

Professional Scrum Master II Course, page 12: ''The Definition of Done is a crucial aspect of transparency. If it is not clear when work is done, then stakeholders may make wrong assumptions about the state of the software.''

B) Developers with an interest in Stella's domain could volunteer to take on this work in their respective Scrum Teams.

This is a good solution because it is consistent with the Scrum value ofcommitment, which means that the Scrum Team members are willing to learn new skills and take on new challenges to deliver value12.By volunteering to take on this work, the Developers can reduce the dependency on Stella, increase their cross-functionality, and collaborate more effectively within and across the Scrum Teams34. F. Ask Stella for a plan to hire and train additional people in her domain, and in the meantime work with the Product Owner and Scrum Teams to re-prioritize the work so that tasks not depending on Stella can be done first

This is another good solution because it is consistent with the Scrum principle ofempiricism, which means that the Scrum Team learns and adapts based on the actual outcomes and feedback, rather than following a predefined plan12. By asking Stella for a plan to hire and train additional people, the Scrum Master can help address the root cause of the dependency and create more capacity and diversity in Stella's domain.By working with the Product Owner and Scrum Teams to re-prioritize the work, the Scrum Master can also help optimize the value and feasibility of the product backlog items, and enable the Scrum Teams to deliver valuable and functional increments every Sprint34. G. Create a team with Stella and identify people from the Scrum Teams to temporarily work in Stella's domain to learn to better serve the existing teams

This is also a good solution because it is consistent with the Scrum value ofrespect, which means that the Scrum Team members appreciate and value each other's skills and perspectives12. By creating a team with Stella, the Scrum Master can acknowledge and leverage Stella's expertise and experience in her domain.By identifying people from the Scrum Teams to temporarily work in Stella's domain, the Scrum Master can also facilitate knowledge transfer and skill development among the team members, which can improve their self-organization and collaboration34.

As a Scrum Master, you are accountable for establishing an environment where the Scrum Team can be effective and deliver valuable products1.One of the ways to do this is by supporting the Product Owner in managing the Product Backlog and engaging with the stakeholders2. In this situation, where there is a performance issue with the product, your best option is:

Encourage the Product Owner to bring the performance concerns to the rest of the Scrum Team and work together to improve the Definition of Done.This option aligns with the principle of empiricism, which is the foundation of Scrum3.Empiricism means that you make decisions based on what is known, rather than what is assumed or predicted3.By encouraging the Product Owner to bring the performance concerns to the rest of the Scrum Team, you are helping them inspect the product Increment and adapt the Product Backlog based on transparent feedback from the stakeholder4. You are also helping them collaborate on improving the Definition of Done, which is a shared understanding of what it means for a product Increment to be complete and potentially releasable. The Definition of Done should reflect the quality standards and expectations of the stakeholders, and should be updated as needed to ensure that the product meets their needs and delivers value.

The other options are not advisable because:

Wait to bring this up in the next Sprint Retrospective as this is the appropriate time for the Developers to re-consider the Definition of Done.This option is incorrect because it contradicts your accountability as a Scrum Master. The Sprint Retrospective is an opportunity for the Scrum Team to reflect on their performance and identify improvements for the next Sprint. However, it is not the only time for them to inspect and adapt their product and process.As a Scrum Master, you should promote continuous improvement and help the Scrum Team address any issues or impediments as soon as they arise1. Waiting to bring this up in the next Sprint Retrospective would mean delaying feedback and action, which can lead to waste or dissatisfaction.

Bring the concern to the quality assurance members of the Scrum Team and ask them to improve how the system is tested.This option is incorrect because it goes against your role as a facilitator, who helps the participants have constructive and respectful conversations. By bringing the concern to only a subset of the Scrum Team, you are creating silos and excluding others from contributing or learning. You are also implying that quality is only their responsibility, rather than a shared accountability of the whole Scrum Team. Moreover, you are not asking them for their input or feedback, but telling them what to do, which can undermine their autonomy and motivation.

Explain to the Product Owner that it is up to the Developers to decide on acceptable performance standards as they own the Definition of Done.This option is incorrect because it contradicts your role as a coach, who helps people grow and improve their skills and behaviors. By explaining to the Product Owner that it is up to the Developers to decide on acceptable performance standards, you are dismissing their concern and creating a gap between them and the Developers. You are also ignoring their valuable perspective and input as a stakeholder representative, who has a clear vision of what value means for the product. Instead of explaining, you should be asking questions and listening actively, and facilitating a dialogue between them and the Developers.