Your multitenant container database (CDB) contains a pluggable database, HR_PDB. The default permanent tablespace in HR_PDB is USERDATA. The container database (CDB) is open and you connect RMAN. You want to issue the following RMAN command: RMAN > BACKUP TABLESPACE hr_pdb:userdata; Which task should you perform before issuing the command? 

Answer options:

A. Place the root container in ARHCHIVELOG mode.
B. Take the user data tablespace offline.
C. Place the root container in the nomount stage.
D. Ensure that HR_PDB is open.

A