Question: What format should be used by a UE when deriving a Network Access Identifier (NAI) from the identity of a selected Public Land Mobile Network (PLMN) while performing EAP-authentication procedure to register to 5GCN via a trusted non-3GPP access network?
Option 1: <any_non_null_string>@nai.5gc.mnc<MNC>.mcc<MCC>
Option 2: <any_non_null_string>@nai.5gc.mnc<MNC>.mcc<MCC>.3gppnetwork.org
Option 3: <any_non_null_string>@tngfid<TNGF ID>.nai.5gc.mnc<MNC>.mcc<MCC>
Option 4: <any_non_null_string>@nai.5gc.nid<NID>.mnc<MNC>.mcc<MCC>
Explanation: According to the provided text, when a UE attempts to register to 5GCN via a trusted non-3GPP access network in a selected PLMN, it should derive a NAI from the identity of the selected PLMN in the format "<any_non_null_string>@nai.5gc.mnc<MNC>.mcc<MCC>.3gppnetwork.org". This is specified to ensure proper identification and connection to the correct PLMN via the trusted non-3GPP access network.