Which two statements about Recovery Manager （RMAN） backups are true？ （）

• A、Online redo log files can be backed up.
• B、Archived redo log files are backed up.
• C、Only used data blocks can be backed up as backup sets.
• D、Only consistent database backups can be performed.
• E、RMAN backup can be taken only if the database is configured in ARCHIVELOG mode.