Question: Upon receiving an SGsAP-IMSI-DETACH-INDICATION message with 'Explicit UE initiated IMSI detach from non-EPS services', how does the VLR update the SGs association for the UE?
Option 1: The VLR marks the SGs association as 'IMSI detached for non-EPS services' and moves the state to SGs-NULL if the name is unchanged.
Option 2: The VLR only updates the UE's detachment status without altering the SGs association state or marking.
Option 3: The VLR changes the state of the SGs association to 'SGs-ACTIVE' for non-EPS services exclusively.
Option 4: The VLR ignores the message if the received name matches the stored one in the VLR.
Explanation: When a VLR receives an SGsAP-IMSI-DETACH-INDICATION with 'Explicit UE initiated IMSI detach from non-EPS services', it marks the SGs association as 'IMSI detached for non-EPS services' and moves the state to SGs-NULL if the received name is unchanged, ensuring a consistent state reflecting both the detachment reason and the updated association status.