After executing the command alter diskgroup disk group2 drop disk dg2a； you issue the following command from the ASM instance：   Select group_number， count（*） from v$asm_operation；   What is the implication if the query against V$ASM_OPERATION returns zero rows？（）  

A.The drop disk operation is still proceeding and you cannot yet run the undrop disks operation.

B.The drop disk operation is complete and you can run the undrop disks command if needed.

C.The drop disk operation is complete and you cannot run the undrop disk command.

D.The query will fail since there is not a V$ASM_OPERATION view available in an ASM instance.

E.None of the above is true.