Answer: (B) Migrating all VMs off the host.
Explanation:
VMs migration is the virtual machine migration that basically change the workloads automatically in the system. The maintenance of the schedule results into the downtime in the server for users. In the mission critical environment, when we performing various types of maintenance operation on the host we first require migrate all the virtual machine.
In the critical environment there is a chance that the data in the given host may be critical and the data in the virtual machine (VM) may be in critical position in the host.