Question: In a 3GPP-compliant system, when the "Bearer-Independent Protocol (BIP)" for Background Data Network (BDN) is enabled, what entity utilizes the Call Control facility to support the BDN service?
Option 1: User Equipment (UE) independently of SIM
Option 2: Mobile Equipment (ME) without SIM involvement
Option 3: Serving and Packet Data Network Gateway (S/P-GW)
Option 4: Subscriber Identity Module (SIM) utilizing the Mobile Equipment's (ME) Call Control facility
Explanation: According to the specifications, when BDN is enabled, it is the SIM that utilizes the Call Control facility of the ME to support the BDN service. This indicates a collaborative interaction where the SIM leverages the ME's capabilities for managing call control aspects necessary for the BDN service, highlighting the interdependence between the SIM and ME in supporting specific services within the 3GPP framework.