How can network administrator provide high availability for APs deployed in an Aruba Mobility Master (MM)-based architecture?

How can network administrator provide high availability for APs deployed in an Aruba Mobility Master (MM)-based architecture?
A . Establish clusters of Mobility Controllers (MCs).
B . Configure MM to provide backup AP tunnel termination in case of controller failure.
C . Deploy all licenses locally yo APs, so that they can continue to function if they lose contact with their controller.
D . Configure APs to convert to controller-less Instant AP mode during controller failure.

Answer: A