You manage a server that runs Windows Server 2008. The windows backup and restore utility is installed ont he server. You nede 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 Caddtarget：C:// /quiet
• C、Wbadmin start backup CallCritical Cbackuptarget：C:// /quiet
• D、Wbadmin start backup CallCritical Cbackuptarget：R：/ quiet