Question: What information is NOT mandatorily required to be transferred from the Media Resource Function Processor (MRFP) to the Delivery Function for Lawful Interception (DF3) via the X3-interface?
Option 1: Identity used for interception
Option 2: Correlation number
Option 3: Time stamp
Option 4: Source IP address of the MRFP
Explanation: According to the context, 'time stamp' is explicitly marked as optional, indicating it is NOT mandatorily required for transfer from MRFP to DF3 via the X3-interface.