You configured the default backup device type as disk for RMAN backups. In your database,because of business requirements,you have to take a simultaneous duplicate backup of the data files when the RMAN BACKUP command is used.  What must you set using the RMAN CONFIGURE command to achieve this?()  
A: MAXSETSIZE TO 2
B: DEVICE TYPE DISK PARALLELISM 2
C: RETENTION POLICY TO REDUNDANCY 2
D: DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 2
出自:Oracle认证