Question: What is the role of the TDF when used for application-based charging in a convergent scenario, specifically with regards to the Gyn reference point?
Option 1: It only performs offline credit control for seamless WLAN offloaded traffic from a 3GPP UE.
Option 2: It only performs online credit control for fixed devices.
Option 3: It allows online credit control for TDF-based charging for both non-seamless WLAN offloaded traffic from a 3GPP UE and for fixed devices.
Option 4: It does not support online credit control in convergent scenarios.
Explanation: The correct answer is Option 3 because the text states that the Gyn reference point allows online credit control for TDF-based charging for both non-seamless WLAN offloaded traffic from a 3GPP UE and for fixed devices, highlighting its role in enabling real-time credit checks for various types of traffic in convergent scenarios.