Question: In a Multi-Party (MPTY) call scenario, as described in security standards for Lawful Interception (LI), what happens to the Conference Controller (CC) links when a target (who is the conference controller) joins two single calls (one active, one held) into a conference?
Option 1: Both sets of CC links are replaced with new ones to handle the conference signals.
Option 2: The CC links from the previously held call are used for the conference, while the active call's links are dropped.
Option 3: The CC links that carried the signals of the active target call are reused for the conference, transmitting the sum signal on the Rx call and the target's signal on the Tx call.
Option 4: All existing CC links are terminated, and new ones are established only after the conference is fully set up.
Explanation: This option correctly describes what happens when a target (acting as the conference controller) merges two single calls into a conference. The existing CC links from the active call are utilized for transmitting and receiving conference signals, ensuring continuity and efficient resource allocation.