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

• A、 The backups consist of backup pieces.
• B、 The datafiles can be multiplexed within the backup.
• C、 The backups can be stored only on the disk.
• D、 While performing the backup across a network， the network bandwidth is reduced.