Question: In a WLAN on GTP S2a/S2 interface, what triggers a Bearer Deactivation event at the PDN Gateway (PDN-GW) that leads to notifying the Delivery Function (DF2)?
Option 1: Successful Authentication of a new User Equipment (UE)
Option 2: Handover from WLAN to a 3GPP Access Network
Option 3: Detection of Detach and PDN Disconnection or PDN GW initiated Resource Allocation Deactivation
Option 4: Periodic Bearer Update due to Inactivity Timer Expiration
Explanation: This is correct because a Bearer Deactivation event is triggered by the detection of either Detach and PDN Disconnection in WLAN on GTP S2a or the PDN GW initiated Resource Allocation Deactivation in WLAN on GTP S2 at the PDN-GW, notifying DF2 with relevant elements if available, highlighting its role in managing and securing bearer resources in non-3GPP accesses like WLAN.