Question: What is the expected behavior of an MME when responding to an Identification Request from another MME in a different serving domain regarding unused EPS authentication data?
Option 1: The MME includes all available EPS authentication vectors to facilitate seamless handover.
Option 2: The MME only shares current EPS security contexts but not the unused vectors.
Option 3: The MME does not distribute unused EPS authentication vectors or non-current EPS security contexts.
Option 4: The MME always includes both used and unused EPS authentication data for security auditing.
Explanation: This behavior maintains the security and integrity of different serving domains by preventing potential security breaches from distributing sensitive information across domain boundaries, aligning with the principle of minimizing exposure of sensitive data.