A Windows server’s backup jobs keep failing with an error message stating that the source drive is not available. After reviewing the logs， which of the following should a technician do FIRST to troubleshoot this issue？（）

• A、Verify the backup media has enough storage space for the backup job
• B、Verify the volume shadow copy service is running
• C、Close all terminal services sessions on the server
• D、Reboot the Windows server and re-run the backup job