Question: Which of the following is NOT a primary function supported by the S1 interface in an Evolved Universal Terrestrial Radio Access Network (E-UTRAN)?
Option 1: Establishment and management of E-UTRAN Radio Access Bearers
Option 2: Direct handling of user plane data between UE and EPC without going through E-UTRAN
Option 3: Transfer of Non-Access Stratum (NAS) signalling messages between User Equipment (UE) and Evolved Packet Core (EPC)
Option 4: Support for location services through the exchange of location requests and information
Explanation: The S1 interface is primarily involved in control plane functions, such as signaling for bearer establishment, handovers, NAS message transfer, and location services. Direct handling of user plane data between UE and EPC typically involves a separate interface for user plane data, not the primary function of the S1 interface which focuses on control plane signaling.