What affect would this command have on the database?

Your database instance is configured with automatic undo management and the
UNDO_RETENTION parameter is set to 900 seconds. You executed the following
command to enable retention guarantee: SQL>ALTER TABLESPACE undotbs1
RETENTION GUARANTEE; What affect would this command have on the database?

A.
The extents in the undo tablespace retain data until the next full database backup

B.
The extents containing committed undo in the undo tablespace are not overwritten
for at least 15 minutes

C.
The extents containing committed data in the undo tablespace are not overwritten
until the instance is shut down

D.
The extents containing committed undo in the undo tablepace are transferred to
Flash Recovery Area before being overwritten