Exam NCP-MCI-7.5 Topic 1 Question 29 Discussion

When Prism Central is scaled out for resiliency, the design goal is not only to have multiple Prism Central VMs, but also to ensure they are not placed together in a way that creates a common point of failure. Nutanix documentation around anti-affinity policies explains that VM-VM anti-affinity is used to keep selected VMs from running on the same host. In a scaled-out Prism Central deployment, this placement separation is the logical next step to strengthen resiliency, because it prevents the Prism Central instances from collapsing onto the same physical host and failing together during a node outage. ( Nutanix ) The other options are either unrelated or not the primary required follow-up. Witness Service is associated with Metro Availability and DR designs, not with the baseline requirement of distributing Prism Central VMs after scale-out. Protection Domain protection may be useful in some cases, but it does not solve co-location risk. HA reservations on the hosting Prism Element cluster address restart capacity, not placement diversity.
The most direct resiliency improvement after scaling out Prism Central is to enforce separation between the Prism Central VMs. That is why D is the best answer. ( Nutanix )