A.the retention period to support flashback
B.the expected length of the longest-running query
C.the number of undo tablespaces in the database
D.the size of the Flash Recovery Area for the database instance

A.It is the time period after which the undo data becomes obsolete.
B.It is the time period after which the committed undo data would be transferred to a temporarytablespace.
C.It is the minimum time period up to which the committed undo data would be retained if free undo spaceis available.
D.It is the time period after which the undo data is transferred to the Flash Recovery Area to provide readconsistency.