Question: In the 5GMM-REGISTERED state, what is a characteristic of the UE's behavior when it is connected via non-3GPP access?
Option 1: The UE may initiate the periodic registration update procedure.
Option 2: The UE shall not initiate the service request procedure.
Option 3: The UE may establish one or more PDU sessions.
Option 4: The UE cannot initiate the non-initial registration procedure for mobility.
Explanation: In the 5GMM-REGISTERED state, when the UE is connected via non-3GPP access, it shall not initiate the periodic registration update procedure. This is a specific behavior characteristic of this state and access type, highlighting an important consideration for network operations and management in 5G systems.