Which two statements are true regarding undo management in the RAC environment?
A.
You can use Automatic Undo Management (AUM) in some of the instances and manual undo management in the rest of the instances in a RAC database.
B.
In a policy-managed RAC database, Oracle automatically allocates the undo tablespace even the Oracle Managed Files (OMF) is disabled in a database.
C.
In a policy-managed RAC database, Oracle automatically allocates the undo tablespace if the database is OMF enabled.
D.
You can dynamically switch undo tablespace assignments by executing the undo tablespace statement from any instance in a administrator managed database.
https://docs.oracle.com/cd/E18283_01/rac.112/e16795/storage.htm
You assign undo tablespaces in your Oracle RAC administrator-managed database by specifying a different value for the UNDO_TABLESPACE parameter for each instance in your SPFILE or individual PFILEs. For policy-managed databases, Oracle automatically allocates the undo tablespace when the instance starts if you have OMF enabled. You cannot simultaneously use automatic undo management and manual undo management in an Oracle RAC database. In other words, all instances of an Oracle RAC database must operate in the same undo mode.