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 Managed Files （OMF）.
• E、Flashback logs are deleted only if you are using Automatic Storage Management （ASM）.