Question: What EAP method is used for registration of a UE to 5GC via an untrusted non-3GPP Access Network?
Option 1: EAP-TLS
Option 2: EAP-PSK
Option 3: EAP-AKA
Option 4: EAP-5G
Explanation: The correct answer is EAP-5G, which is a vendor-specific EAP method used for encapsulating NAS messages between the UE and the N3IWF during registration via untrusted non-3GPP access.