What are the two main benefits that block media recovery provides over file-level recovery?

Oracle 10g support block media recovery. This reduces the smallest until of recovery from a data file to a database block. What are the two main benefits that block media recovery provides over file-level recovery? (choose two)

A.
supports incomplete recovery

B.
does not require Recovery Manager

C.
lowers the mean time to recover

D.
allows increased data availability during media recovery

Explanation:
If a small number of blocks within one or more datafiles are corrupt, you can perform block media recovery instead of restoring the datafiles from backup and performing complete media recovery of those files. The Recovery Manager BLOCKRECOVER command can be used to restore and recover specified data blocks while the database is open and the corrupted datafile is online.Block media recovery may be better than datafile media recovery if availability is critical. While block media recovery is possible even if you do not base your backup and recovery strategy on RMAN, RMAN-based block media recovery can be performed more quickly and with less effort .

REF: Oracle(r) Backup and Recovery Advanced User’s Guide, 2-2 and 2-5