You work as a database administrator at Certkiller .com. Your database is open and running in ARCHIVELOGmode. You take RMANfull backups every Sunday night. On Monday morning， while querying the user1.employeestable， you receive the following error message： 01578： ORACLE data block corrupted （file # 5， block # 51） ORA-01110： data file 5：’/u01/app/oracle/oradata/orcl/example01.dbf’ You need to rectify the corruption while ensuring the following： The data file should remain online. The mean time to recover （MTTR） should be minimal. You are not using a backup control file and all the archived logs are accessible. Which option would you choose？（）

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 point-in-time recovery