what happens to disks that are already a part of the same or another disk group?

If you use ALTER DISKGROUP ADD DISK and specify a wildcard for the discovery string, what
happens to disks that are already a part of the same or another disk group?

A.
The command fails unless you specify the FORCE option.

B.
The command fails unless you specify the REUSE option.

C.
The command must be reissued with a more specific discovery string.

D.
The other disks, already part of the disk group, are ignored.