What should you back up?

Your network contains an Active Directory domain named contoso.com.
All servers run Windows Server 2012 R2.
The network contains a System Center 2012 R2 Data Protection Manager (DPM) deployment.
The domain contains six servers.
The servers are configured as shown in the following table.

You install System Center 2012 R2 Virtual Machine Manager (VMM) on the nodes in Cluster2.
You configure VMM to use a database in Cluster1. Server5 is the first node in the cluster.
You need to back up the VMM encryption key.
What should you back up?

A.
A full system backup of Server1

B.
A full system backup of Server3

C.
A backup of the Windows\\DigitalLocker folder on Server5

D.
A backup of the Windows\\DigitalLocker folder on Server1

Explanation:
The VMM Encryption key is stored on the VMM server by default. But for Highly Available VMM setups (when VMM is running in a CLUSTER) the Encryption
key is stored in Active Directory.
To back up the encryption key we perform a full system Backup of AD.