You are managing a single instance Oracle 10g database that utilizes the following parameters： Which of the following set of commands must you execute to enable Flashback Database？（）

A.   STARTUP MOUNT EXCLUSIVE  ALTER DATABASE FLASHBACK ON；  ALTER DATABASE OPEN；

B.   STARTUP MOUNT  ALTER DATABASE FLASHBACK ON；  ALTER DATABASE OPEN RESETLOGS；

C.   STARTUP MOUNT EXCLUSIVE  ATLER DATABASE ARCHIVELOG；  ALTER DATABASE FLASHBACK ON；  ALTER DATABASE OPEN RESETLOGS；

D.   STARTUP MOUNT  ALTER DATABASE ARCHIVELOG；  ALTER DATABASE FLASHBACK ON；  ALTER DATABASE OPEN；