Question: In a multi-MC (Mission Critical) system scenario, when an MC service client initiates an ad hoc group emergency alert cancel request, what information MUST be included in the request if it's sent for another user who initiated the emergency alert?
Option 1: The cancelling user's location information
Option 2: The ID of the MC system where the alert was initially raised
Option 3: The MC service ID of the user who initiated the emergency alert
Option 4: The type of emergency that was alerted
Explanation: This is crucial for authorization and verification purposes. By including the MC service ID of the user who initiated the emergency alert, the MC service server can properly validate the request against the original alert initiator, ensuring only authorized cancellations are processed, especially in interconnected MC systems where multiple users and systems are involved.