A company is using Replication Manager to backup their Microsoft Exchange 2010 environment using Microsoft Volume Shadow Service (VSS). Each Exchange database and log volume has separate Symmetrix VMAX LUNs. A Replication Manager backup job for a Microsoft Exchange 2010 server with 20 databases keeps failing to complete a backup.
What could be causing the failure?

A.
Snapshot timeouts are occurring

B.
A virtual mount host is being used for the replicas

C.
Consistency checks are being run in parallel

D.
Insufficient number of gatekeepers have been configured