Which statement is true concerning dropping a pluggable database (PDB)?
A.
The PDB must be open in read-only mode.
B.
The PDB must be in mount state.
C.
The PDB must be unplugged.
D.
The PDB data files are always removed from disk.
E.
A dropped PDB can never be plugged back into a multitenant container database (CDB).
Explanation:
http://docs.oracle.com/database/121/ADMIN/cdb_plug.htm#ADMIN13658