To maintain high availability in the case of a node failure in a two-node cluster, a Witness VM is required. Therefore, the correct answer is A. The Witness VM acts as a tie-breaker and arbitrator in the event of a split-brain scenario, where both nodes lose connectivity to each other, to ensure that only one node continues to operate and serve workloads. It is also recommended to use a high-performance network to minimize network latency between the two nodes and the Witness VM.

When updating the LCM Framework on a dark site web server, the LCM Framework Bundle should be extracted to the 'release' directory. This directory is specifically designated for holding the updated LCM Framework files, and the update process will look for the files in this location. Extracting the bundle to a different directory, such as 'upgrade', 'software' or 'install' would not be sufficient as the LCM Framework update process may not be able to find the files. Reference: https://portal.nutanix.com/page/documents/details?targetId=LCM-Guide-v2_11:lc-updating-the-lcm-framework_lc-updating-the-lcm-framework.html

Role-based access control (RBAC) allows administrators to configure access control for different users and groups in the Nutanix cluster. This feature is available through Prism Central, where administrators can configure roles and permissions for different users and groups. Reference:https://portal.nutanix.com/page/documents/details?targetId=Platform-Administrator-Guide-v5_7:pag-user-role-c.html

A vDisk is a file that is stored on storage devices owned by a CVM. A vDisk represents a virtual disk that is attached to a VM or a CVM. A Storage Pool is a logical grouping of physical disks in a cluster. An Extent Group is a collection of data blocks that belong to a vDisk. A Container is a logical grouping of vDisks that share the same storage policies and settings. Reference: https://www.nutanix.com/content/dam/nutanix/resources/misc/ebg-nca-6-5.pdf (pages 31-32)