Which configuration task fixes the issue?

Two cisco 5520 wireless LAN controllers are managing all access points throughout the network. The WLCs are in different locations to provide geographical redundancy a mobility group has been configured on both WLCs and has a UP status on both controllers. The Aps in location A are statically configured to use controller A as the primary and controller B as the secondary. If the WLC in location A goes offline. The Aps successfully join the WLC in location, but they do not fail over to their primary configured controller .

Which configuration task fixes the issue?
A . Configure the WLC in location A as primary using the CAPWAP AP Controller IP Address command on all the location A Access points.
B . Use DHCP Option 43 and specify WLC in location A as primary.
C . Enable AP fallback globally on the WLC
D . Change the AP Failover Priority to critical.

Answer: A