You have a production instance running on your server. UNDO_RETENTION is not long enough to satisfy read-consistency requirements. How do you change the UNDO_RETENTION value？（）

A.You are working on a database where downtime is not tolerated.
B.You are working on a database where downtime can be tolerated.
C.You are working on a database that operates in ARCHIVELOG mode.
D.You are working on a database that operates in NOARCHIVELOG mode.
E.You are working on a database where all the tablespaces are locally managed.
F.You are working on a database where control files and redo log files are multiplexed.
G.You are working on a database where control files and redo log files are not multiplexed.

A.The database remains open.
B.The database gets dismounted.
C.The database becomes read only.
D.The database instance gets aborted.
E.The database gets shut down automatically.
F.The status of the database depends on the status of the USERS tablespace.

A.data files
B.control files
C.tablespaces
D.password file
E.parameter file
F.whole database
G.flashback log file
H.archived log files
I.change tracking file