If the Cisco WLAN controller cannot reach the primary AAA server, it will proceed to the next server on the list by priority index. The Cisco WLAN controller will return to the primary AAA server, when reachable, upon which of these events?
A.
The primary server has just become reachable.
B.
The secondary server is unreachable.
C.
The primary server has been active for a preset dead-server time.
D.
The secondary server has been used for a preset dead-server time.