How many handsets are located on the 737?

The total number of handsets located on the Boeing 737 corresponds to having one handset at each cabin jumpseat. This design ensures that flight attendants stationed at these jumpseats can effectively communicate with the cockpit and coordinate during various phases of the flight, particularly during emergencies or when providing passenger service. Each jumpseat is positioned strategically to maximize the effectiveness of communication across the cabin, allowing attendants to respond promptly to any situation that may arise.

The other options indicate different configurations or quantities of handsets that do not accurately reflect the specific arrangement found on the 737. For instance, having two in the cockpit would only pertain to communication within the cockpit area, not addressing the needs in the cabin. Similarly, mentioning three in the main cabin or four scattered throughout the aircraft suggests a distribution pattern that isn't aligned with the standard setup designed for optimal communication efficiency in an aircraft.