vCenter Server is running within a virtual machine (VM) that is part of a VMware HA
and
DRS cluster. The vCenter VM can migrate between all hosts in the cluster by using
VMotion. DRS is configured for partial automation. What happens if the ESX host that is
currently running the vCenter VM experiences a power outage?

A.
This situation cannot occur because vCenter cannot be installed on a VMware HA
cluster.

B.
All DRS cluster operations will be unavailable until the ESX host is brought back
online.

C.
vCenter will stay offline, but all virtual machines on the remaining hosts will continue
without interruption.

D.
VMware HA will restart the vCenter VM on another host.

Explanation:
vSphere Availability Guide ESX 4.0 ESXi 4.0 vCenter Server 4.0, Page 11.
VMware HA provides high availability for virtual machines by pooling them and the
hosts they reside on into a cluster. Hosts in the cluster are monitored and in the event of a
failure, the virtual machines on a failed host are restarted on alternate hosts.