Which three statements are true about undo management in a RAC environment? (Choose three.)

A: You can dynamically assign a newly created undo tablespace to an instance. B: In a policy-managed RAC database, an undo tablespace may automatically be created if OMF is enabled for the database. C: An instance that performs instance recovery can write to the undo tablespace of a failed instance. D: A mixture of automatic undo management and manual undo management is supported within a RAC database. E: It is necessary to assign a specific undo tablespace to a specific instance.