you manage a server that runs windows server 2008. The windows backup and restore utility is installed on the server. You need to create a full backup of all system state data to the DVD drive (R: drive) on the server. Which command should you run on the server?（）

A. WBadmin enable backup –addtarget:R: /quiet.
B. Wbadmin enable backup –addtarget:C: /quiet.
C. Wbadmin start backup –allCritical –backuptarget:C: /quiet.
D. Wbadmin start backup –allCritical –backuptarget:R:/ quiet.