which stack state refuses UpdateStack calls?

For AWS CloudFormation, which stack state refuses UpdateStack calls?

A.
UPDATE_ROLLBACK_FAILED

B.
UPDATE_ROLLBACK_COMPLETE

C.
UPDATE_COMPLETE

D.
CREATE_COMPLETE

Explanation:
When a stack is in the UPDATE_ROLLBACK_FAILED state, you can continue rolling it back to return it to a working state
(to UPDATE_ROLLBACK_COMPLETE). You cannot update a stack that is in the UPDATE_ROLLBACK_FAILED state.
However, if you can continue to roll it back, you can return the stack to its original settings and try to update it again.
http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stackscontinueupdaterollback.html