How can you reverse the effects of an ALTER DISKGROUP ... DROP DISK command if it has already completed？（）  

• A、 Issue the ALTER DISKGROUP ... ADD DISK command.
• B、 Issue the ALTER DISKGROUP ... UNDROP DISKS command.P.... DROP DISK CANCEL command.
• C、 Issue the ALTER DISKGROU
• D、 Retrieve the disk from the Recycle Bin after the operation completes.