You are managing an ASM instance. You previously issued the following statements： ALTER DISKGROUP dg1 DROP DISK disk2； ALTER DISKGROUP dg1 DROP DISK disk3； ALTER DISKGROUP dg1 DROP DISK disk5； You want to cancel the disk drops that are pending for the DG1 disk group. Which statement should you issue？（）

ALTER DISKGROUP dg1 UNDROP disk2，disk3，disk5
B. ALTER DISKGROUP dg1 UNDROP
C. ALTER DISKGROUP dg1 UNDROP DISKS
D. You cannot cancel the pending disk dro