Question: In the context of Lawful Interception (LI) over the X2-interface, what is the primary purpose of transferring a 'Correlation Number' from entities like the HLR to the Delivery Function 2 (DF2)?
Option 1: To ensure Quality of Service (QoS) for intercepted communications.
Option 2: For encrypting packet data headers in real-time.
Option 3: To facilitate location-dependent interception by correlating target locations.
Option 4: To link multiple pieces of intercepted data to a single target identity across different sessions.
Explanation: The Correlation Number is crucial for linking various intercepted data elements (e.g., voice, data, location) to the same target, ensuring that all relevant information related to a specific target identity can be accurately aggregated and analyzed by Law Enforcement Agencies, thereby facilitating effective lawful interception.