问题：

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These are the details about V$FLASHBACK_DATABASE_STAT： SQL> DESC v$FLASHBACK_DATABASE_STAT 
Name                    Null？              Type 
------------- -------- -------------- 
BEGIN_TIME                               DATE 
END_TIME                                 DATE 
FLASHBACK_DATA                        NUMBER 
DB_DATA                                  NUMBER 
REDO_DATA                               NUMBER 
ESTIMATED_FLASHBACK_SIZE             NUMBER 
Which two statements regarding the V$FLASHBACK_DATABASE_STATview aretrue？ （）

A .  BEGIN_TIME is the time at which Flashback logging is enabled.
B .  END_TIME is the time at which the query is executed on the view.
C .  REDO_DATA is the number of bytes of redo data written during the interval.
D .  This view contains information about flashback data pertaining to the last 24 hours.
E .  FLASHBACK_DATA is the amount of flashback data generated since the database was opened.