Deauthentication is the correct answer because it is classically effective against WPA2 wireless networks, while WPA3 includes protections against unauthenticated deauthentication management-frame abuse when properly implemented with Protected Management Frames. Since AP3 is the only access point using WPA2, it is the only one that clearly remains the specific target for this attack in the scenario. A deauthentication attack forces connected clients off the network, often to capture handshakes or to push users toward reconnect behavior during wireless assessments. Brute force is not exclusive to AP3 in the way this question asks, signal jamming can affect any wireless network regardless of security standard, and evil twin attacks are not limited only to WPA2 networks. Therefore, the attack that applies only to AP3, based on its WPA2 configuration, is deauthentication.