During a fire-fighting scenario, which information must cabin crew relay to the flight deck?

The correct answer focuses on the essential information that cabin crew must communicate to the flight deck during a fire-fighting scenario. Relaying details about the location of the fire, its intensity, the source of the fire, and the actions being taken by the crew allows the flight deck to assess the situation accurately and make informed decisions regarding flight safety, potential emergency landings, and communication with emergency services.

Understanding the intensity and source of the fire is crucial for the flight crew as it helps evaluate the severity of the situation and the possible risks involved. Moreover, knowledge about the actions being taken by the cabin crew provides insight into immediate fire control efforts and allows for coordination of further safety measures. This comprehensive situational awareness is essential for effective management of the emergency.

Other choices do not cover all critical aspects that should be communicated. For example, relaying coordinates or smoke detection may be useful in some contexts but does not encompass the immediate actions and the nature of the fire that are vital for the flight deck's understanding. Therefore, the most effective and comprehensive choice is the one that includes the four key elements of location, intensity, source, and actions taken, representing a complete picture for effective decision-making under pressure.