Which task should you perform before issuing the command?

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?

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.

Explanation:
RMAN> select name,open_mode from v$pdbs;
using target database control file instead of recovery catalog NAME OPEN_MODE
——————– ——-
PDB$SEED READ ONLY
ORA12P1 READ WRITE
ORA12P2 MOUNTED
RMAN> backup tablespace ora12p2:users;
Starting backup at 31-MAR-14
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=137 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00013
name=/appl/oradata/cdbroot/ORA12C1/F5D05369C4B23E83E0430100007F6D99/datafile/o1_mf_users
_9mhr0o5l_.dbf
channel ORA_DISK_1: starting piece 1 at 31-MAR-14
channel ORA_DISK_1: finished piece 1 at 31-MAR-14
piece handle=/appl/oradata/flash_recovery/ORA12C1/F5D05369C4B23E83E0430100007F6D99/backupset/2014_
03_31/o1_mf_nnndf_TAG20140331T001832_9mhzdb6w_.bkp tag=TAG20140331T001832 com- ment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01 Finished backup at 31-MAR-14
Starting Control File and SPFILE Autobackup at 31-MAR-14
piece handle=/appl/oradata/flash_recovery/ORA12C1/autobackup/2014_03_31/o1_mf_s_843610715_9mhzdcv8 _.bkp
comment=NONE
Finished Control File and SPFILE Autobackup at 31-MAR-14
RMAN>
The above example illustrates that if root container is open and in archivelog it can do the backup of tablespace
whether the pdb is mounted or open.