Question: In a UE (User Equipment) utilizing ProSe UE-to-network relay for Mission Critical (MC) services, which of the following functional entities is NOT primarily associated with common services?
Option 1: Key Management Client
Option 2: MC Service Client
Option 3: Signalling User Agent
Option 4: Group Management Client
Explanation: The question requires identifying a functional entity not primarily associated with common services in the context of UE utilizing ProSe for MC services. - Key Management Client (Option 1), Group Management Client (Option 4) are mentioned as part of common services. - Signalling User Agent (Option 3) is listed under signalling control, which could be considered tangential to both common and MC services but isn't the best fit for this question's criteria. - MC Service Client (Option 2) is explicitly described in relation to MC services with relevant application functions defined in the corresponding MC service TS, making it the entity NOT primarily associated with common services.