Question: In a conformance testing scenario for User Equipment (UE), what is the expected response from the UE after receiving a `RRC CONNECTION SETUP` message from the Serving System (SS) in response to its initial `RRC CONNECTION REQUEST`?
Option 1:  `RRC CONNECTION RELEASE` message, indicating an error in setup
Option 2: `RRC CONNECTION RECONFIGURATION COMPLETE` message, adjusting settings
Option 3: `RRC CONNECTION SETUP COMPLETE` message, confirming successful setup
Option 4: `RRC CONNECTION REQUEST` repeat, due to incomplete information
Explanation: In the context of RAN procedures for UE connection establishment, after the SS sends a `RRC CONNECTION SETUP` message in response to the UE's `RRC CONNECTION REQUEST`, the UE is expected to confirm the successful setup by sending an `RRC CONNECTION SETUP COMPLETE` message. This message signifies that the UE has successfully applied the configuration and is ready for further communication, highlighting its importance in telecom session management.