You need to ensure that the domain controllers can be recovered in the event of a failure

Your environment contains one Active Directory Domain Services (AD DS) domain. All domain
controllers have Windows Server 2012 R2 installed. All domain controllers are virtualized domain
controllers.
You design a disaster recovery strategy. You have the following requirements:
The domain controllers can be recovered in the event that a Hyper-V host server fails.
The AD DS domain must be restorable to a consistent state.
You must minimize the data loss.
You need to ensure that the domain controllers can be recovered in the event of a failure. What
should you do?

A.
Clone the domain controller that holds the PDC Emulator role to a different Hyper-V host server.
Schedule a Windows PowerShell job to run the Checkpoint-VM cmdlet on each virtual domain
controller.

C.
Run Windows Azure Hyper-V Recovery Manager.

D.
On each guest operating system, run Windows Server Backup.

E.
on the host operating system, run Windows Server Backup.

F.
Schedule a Windows PowerShell job to back up each domain controller’s virtual hard disk (VHD)
file.