A network engineer is configuring high availability on an access point.

When configuring high availability on a Cisco access point, the AP can be configured with a maximum of three controllers: a primary controller, a secondary controller, and a tertiary controller. This three-tier hierarchy defines the failover order — the AP first attempts to join its primary controller, then the secondary if the primary is unavailable, and finally the tertiary if both the primary and secondary are unreachable. After exhausting all three configured options, the AP enters a discovery process to find any available controller. This three-controller configuration (primary, secondary, tertiary) allows network engineers to implement N+1 redundancy where critical APs can be directed to specific backup controllers in a deliberate sequence. Limiting the configuration to only 2 controllers (as stated in Option B which would be incorrect) would reduce redundancy options for environments with geographically distributed controllers requiring specific failover paths. Reference: WLSD Study Guide — AP High Availability Configuration, Primary/Secondary/Tertiary Controller Assignment, AP Failover Design.