What does Garbage Collection do?

A.
Deletes an object by overwriting with specific bit patterns

B.
Automatically tracks and manages object references on the Centera and deletes the CDFs no longer referenced by BLOBs

C.
Manually manages object references and delete BLOBs completely that are no longer referenced by a CDF

D.
Automatically tracks and manages object references on the Centera and deletes BLOBs no longer referenced by a CDF