Your network contains a server named Server1 that runs Windows Server 2008 R2. The disks on Server1 are configured as shown in the following table. Disk name Disk type Disk 0 Internal hard disk drive Disk 1 External hard disk drive Disk 2 Virtual hard disk You run the Backup Once wizard and discover that the option for Full Server backup is unavailable. You need to ensure that you can run a full server backup of Server1. What should you do？（）

A. Take Disk 1 offline.
B. Take Disk 2 offline.
C. Run the Set-WBPolicy cmdlet.
D. Run Windows Server Backup as an Administrator.