Which two statements are true about the configuration and use of UNDO?

Active UNDO is always retained.

Unexpired UNDO is always retained.

UNDO_RETENTION specifies for how long Oracle attempts to keep expired and unconsumed UNDO.

UNDO_RETENTION specifies how long all types of UNDO are retained.

UNDO_RETENTION specifies for how long Oracle attempts to keep unexpired UNDO.