What is the purpose of the "breakaway" feature in certain air brake systems?

Answer: B — To activate the emergency brakes if the trailer disconnects from the tractor

The purpose of the "breakaway" feature in certain air brake systems is to activate the emergency brakes if the trailer disconnects from the tractor. This feature is crucial for safety, as it ensures that in the event of a trailer being inadvertently detached while the vehicle is in motion, the brakes will automatically engage, preventing the trailer from rolling away and potentially causing accidents or injuries. The breakaway system typically consists of a cable that links the trailer to the tractor; if the trailer becomes uncoupled, this cable pulls on a mechanism that triggers the braking system, thus providing a critical safety measure for both the vehicle operator and others on the road.