You work as a database administrator for Supportcenter.cn. You received the following error while working on your database: ORA-01555: snapshot too old ,In which situation would you receive such an error?()
A.You performed rollback after commit.
B.If a log switch occurs in your database.
C.Thearchiverfails to generate an archived log file.
D.Instance recovery fails to find one of the redo log files.
E.A long-running query is unable to get read-consistent image.
F.If you perform manual undo management operations in auto mode.