You issued the RMAN>SHOW ALL； command. The output of the command is as follows：     After analyzing this output， what conclusion can you draw？ （）

• A、 If you perform a backup across a network， then the backup will reduce the bandwidth.
• B、 If you perform a backup of a datafile， then the backup will be the same as the operating system copy of the datafile.
• C、 If you perform a backup of a single datafile， then the control file will not be backed up. 
• D、 The maximum size of each backup set is 10MB
• E、 The backups will be performed on the disk.