The UNDO_RETENTION parameter in your database is set to 1000 and undo retention is not guaranteed. Which statement regarding retention of undo data is correct?

• A. Undo data becomes obsolete after 1,000 seconds
• B. Undo data gets refreshed after every 1,000 seconds
• C. Undo data will be stored permanently after 1,000 seconds
• D. Committed undo data would be retained for 1,000 seconds if free undo space is available