You can use Oracle Flashback to look at past activity in your database. What are two other characteristics of Oracle Flashback？（）

A.Oracle Flashback uses undo information to construct consistent data. 
B.You can use a cursor opened while using an Oracle Flashback image to perform DML once you deactivate Oracle Flashback in your session. 
C.You can only use Oracle Flashback view of the data if the required records are still in the online redo log files. 
D.Oracle Flashback lists the DML that was executed during the period you identify when initiating your session.