【单选题】

You have enabled backup optimization in RMAN. You issue the following RMAN command to configure a redundancy-based retention policy：   CONFIGURE RETENTION POLICY TO REDUNDANCY 3；   Which statement is true？（）  

A、  The command fails because you cannot configure a redundancy-based retention policy when backup  optimization is enabled

B、  Backup optimization is performed， but RMAN considers the redundancy-based retention policy when it determines which datafiles should be backed up

C、  Backup optimization is permanently disabled

D、  Backup optimization is temporarily disabled because a redundancy-based retention policy is specified

  题目答案

  答案解析

略