Question: What is the primary purpose of including Mobile Terminated Calls (MTCs) in the CDRs for the TAP, even if they are zero-priced in the visited network?
Option 1: To calculate roaming charges for the visiting subscriber.
Option 2: To determine the re-routing charges from the HPLMN to the VPLMN.
Option 3: To provide detailed billing information to the home subscriber.
Option 4: To enable the home network to verify the authenticity of the CDRs.
Explanation: The correct answer is Option 2 because, according to the text, even if MTCs are zero-priced in the visited network, the TAP records are still required by the home network to determine the re-routing charges from the HPLMN to the VPLMN. This highlights the importance of including MTCs in the CDRs for accurate charging and billing purposes.