If a load extends at least 4 feet beyond the bed of a vehicle, what must be displayed at the extreme end of the load?

When a load extends at least 4 feet beyond the bed of a vehicle, it is required to display a red flag or a red light at the extreme end of the load to ensure visibility and safety on the road. The correct option in this context is a flag, which serves to alert other drivers to the presence of an extended load, particularly in daylight conditions. This requirement is aimed at preventing accidents by increasing the awareness of other road users regarding the size and dimensions of your vehicle and its load. Reflectors and lamps are typically associated with ensuring visibility during nighttime or low-light conditions, while a flag, particularly in bright red, is a clear and immediate signal to other drivers about the unusual protrusion of the load.