Question: When is the Requested NSSAI IE included by the UE during the registration procedure?
Option 1: Only when the 5GS registration type IE indicates "periodic registration".
Option 2: Only when the 5GS registration type IE indicates "emergency registration".
Option 3: When the 5GS registration type IE indicates either "initial deregistration" or "mobility deregistration updating".
Option 4: When the 5GS registration type IE indicates either "initial registration" or "mobility registration updating".
Explanation: The Requested NSSAI IE is included by the UE during the registration procedure when the 5GS registration type IE indicates either "initial registration" or "mobility registration updating", as specified in subclauses 5.5.1.2.2 and 5.5.1.3.2, respectively. This ensures that the UE provides the necessary information for the network to process the registration request accordingly.