You are working on the APPDB database as a DB A. The database has a default Flashback Data Archive DFLA1 created on it. You issued the following command to drop the Flashback Archive FLA1：   DROP FLASHBACK ARCHIVE fla1；   What is the effect of this command？（）

• A、 The Flashback Archive FLA1 is dropped only if it is empty.
• B、 The tablespace having Flashback Archive is dropped.
• C、 The Flashback Archive FLA1 is dropped after moving the existing data in it to the default Flashback Archive.
• D、 The Flashback Data Archive and historical data are dropped.