Which three statements are true about the startup and shutdown of multitenant container databases (CDBs) and pluggable databases (PDBs)?
A. A PDB opened in restricted mode allows only local users to connect.
B. When a CDB is open in restricted mode, PDBs must also be opened in restricted mode.
C. When a CDB is in mount state, PDBs are automatically placed in mount state.
D. All PDBs must be shut down before shutting down a CDB instance.
E. When a CDB instance is started, PDBs can be placed in open state by using database triggers or by executing the alter pluggable database command.