A complete database backup to media is taken for your database every day. Which three actions would you take to improve backup performance? 

Answer options:

A. Set the backup_tape_io_slaves parameter to true.
B. Set the dbwr_io_slaves parameter to a nonzero value if synchronous I/O is in use.
C. Configure large pool if not already done.
D. Remove the rate parameter, if specified, in the allocate channel command.
E. Always use RMAN compression for tape backups rather than the compression provided by media manager.
F. Always use synchronous I/O for the database.

BCD

Reference: http://docs.oracle.com/cd/B19306_01/backup.102/b14191/rcmtunin.htm