You disabled the Flashback Database feature by using the following command：  SQL> ALTER DATABASE FLASHBACK OFF；  What would be the effect of this command on the existing flashback logs？（）

• A、 Flashback logs are not deleted.
• B、 Flashback logs are deleted automatically.
• C、 Flashback logs are deleted only if you are using Recovery Manager （RMAN）
• D、 Flashback logs are deleted only if you are using Oracle Manager Files （OFM）
• E、 Flashback logs are deleted only if you are using Automatic Storage Management （ASM）