How is 'Souls on Board' typically communicated?

'Souls on Board' is a critical piece of information that indicates the total number of people onboard an aircraft, which is essential for safety and operational purposes. This information is typically communicated to air traffic control prior to the flight, specifically during the pre-flight procedures.

Communicating 'Souls on Board' to air traffic control allows them to have an accurate understanding of the aircraft's configuration and is crucial in the event of an emergency or if an evacuation is required. This information helps in ensuring that emergency services are ready and can act appropriately based on the number of passengers and crew members that may need assistance.

While the other options involve communication or record-keeping related to passengers, they do not specifically relate to the standard procedure of notifying air traffic control about the number of individuals on the aircraft before takeoff. This makes the communication during the pre-flight briefing to air traffic control the most relevant context for declaring 'Souls on Board.'