Question: In a Lawful Interception scenario, what triggers the 'Cancel Location' event report from the Serving System (SGN) to the Delivery Function 2 (DF2), and what key information is conveyed in this report?
Option 1: The 'Cancel Location' event is triggered by a UE's (User Equipment) handover to a new cell, reporting the new serving system's ID to DF2.
Option 2: This event is initiated when a subscriber's data is updated in the HLR (Home Location Register), sending the subscriber's new profile to DF2.
Option 3: The 'Cancel Location' report to DF2 occurs upon receipt of a paging request from the MME (Mobility Management Entity), including the target UE's IMSI (International Mobile Subscriber Identity).
Option 4: The event is triggered when the HLR sends a cancel location or purge command to the SGN, reporting the previous serving system of the target to DF2.
Explanation: This question assesses understanding of lawful interception procedures within telecom networks. The correct answer accurately reflects the trigger for the 'Cancel Location' event as specified - the receipt of a cancel location or purge command from the HLR to the SGN, with the report including details about the previous serving system of the target, crucial for maintaining accurate location information during lawful interception activities.