When operating with a Mode 1 transponder, which of the following indicates a request for direct support from another aircraft?

Answer: B — Squawk 72

When operating with a Mode 1 transponder, squawking 72 is the designated code that indicates a request for direct support from another aircraft. This specific code is utilized to signal that the aircraft requires assistance or is seeking specific help from surrounding aircraft. In air traffic management, transponder codes serve as a communication method for pilots to convey different statuses and requests to air traffic control and other aircraft. Each code corresponds to specific operational needs or conditions. When an aircraft squawks 72, it effectively signals its intent for direct support, facilitating a prompt and coordinated response from nearby pilots and air traffic control. Understanding the significance of these squawk codes is crucial for effective communication and situational awareness in aviation.