When is the UNDO_RETENTION parameter value ignored by a transaction?
A.
when the data file of the undo tablespace is autoextensible
B.
when there are multiple undotablespaces available in a database
C.
when the undo tablespace is of a fixed size and retention guarantee is not enabled
D.
when Flashback Database is enabled
Explanation:
Reference:
http://docs.oracle.com/cd/B19306_01/server.102/b14231/undo.htm (undo retention, see the bullets)
C