Question: When is the UE required to include the Additional 5G security information in the NAS message container?
Option 1: During every registration procedure.
Option 2: Only when the AMF includes the SECURITY MODE COMMAND message with the RINMR bit set to "Retransmission of the initial NAS message requested".
Option 3: When the UE has a valid 5G NAS security context.
Option 4: If during an ongoing registration procedure or service request procedure, the AMF included the Additional 5G security information with the RINMR bit set to "Retransmission of the initial NAS message requested" in the SECURITY MODE COMMAND message, or if the UE does not have a valid 5G NAS security context.
Explanation: The correct answer is Option 4 because it accurately reflects the conditions under which the UE is required to include the Additional 5G security information in the NAS message container. This includes two scenarios: (a) when the AMF requests retransmission of the initial NAS message, and (b) when the UE lacks a valid 5G NAS security context during an ongoing registration procedure.