Which behavior occurs when Cisco UCM has a CallManager group that consists of two subscribers?

Which behavior occurs when Cisco UCM has a CallManager group that consists of two subscribers?

A. Endpoints attempt to register with both subscribers in a load-balanced method. B. Endpoints attempt to register with the bottom subscriber in the list. C. Endpoints attempt to register with the top subscriber in the list. D. If a subscriber is rebooted, endpoints deregister until the rebooted system is back in service.