You observe that database performance has degraded over a period of time. While investigating the reason， you find that the size of the database buffer cache is not large enough to cache all the needed data blocks. 
Which advisory component would you refer to， in order to determine the required size of the database buffer cache？（）

A.BMR lowers the mean time to recover （MTTR）.
B.BMR supports point­in­time recovery of individual data blocks.
C.BMR enables you to use incremental backups for block recovery.
D.BMR enables recovery even when the database is not mounted or open.
E.BMR enables you to use proxy backups to perform block media recovery.
F.BMR enables increased availability of data during recovery because the data file that requires a recovery can remain online.

A.create a backup of the database and recover all corrupted blocks found in the backup
B.run a backup validation and list all the logically corrupt blocks as well as physically corrupt blocks in the database
C.run a backup validation to populate V$COPY_CORRUPTION view， and then list any corrupt blocks recorded in the view
D.run a backup validation to populate V$DATABASE_BLOCK_CORRUPTION view， and then repair any corrupt blocks recorded in the view
E.run a backup validation， repair any corrupt blocks found during the validation process， and then update V$DATABASE_BLOCK_CORRUPTION view to indicate which corrupt blocks have been repaired

A.flash back the corrupted blocks
B.use the DBMS_REPAIR package
C.use the RMAN TSPITR command
D.use the RMAN BLOCKRECOVER command
E.use the RESTORE DATABASE and RECOVER DATABASE commands
F.investigate the time at which the corruption occurred and perform a point­in­time recovery