Question: What authentication method is used by the 5GC to authenticate an AUN3 device behind a 5G-RG?
Option 1: EAP-AKA'
Option 2: EAP-TLS
Option 3: EAP-PSK
Option 4: PEAP
Explanation: According to the security architecture and procedures for 5G System, an AUN3 device behind a 5G-RG is authenticated by the 5GC using EAP-AKA', as specified in RFC 5448. This method is specifically defined for this scenario, ensuring secure authentication of devices connected through a 5G-RG.