Vehicles should be equipped with a horn that can be heard from what minimum distance?

The correct choice is based on safety regulations that dictate the minimum sound level for vehicle horns. A vehicle's horn should be audible from a minimum distance of 200 feet to ensure that it can alert others on the road effectively, which is particularly important in preventing accidents. This distance allows drivers, pedestrians, and cyclists enough time to react to the approaching vehicle, helping to enhance overall road safety.

The other distances, although they may seem reasonable, do not meet the required standards for ensuring adequate notification of other road users. A horn that can only be heard from 100 feet or even 150 feet may not provide sufficient warning in situations where immediate action is necessary to avoid a collision or hazard.