547.Traffic control signals use red, yellow, and green lights to regulate the movement of vehicles on the road.Which of the following correctly describes the function of traffic control signals?
(A) Red and yellow lightsflash alternately to warn drivers to slow down or stop before proceeding.
(B) Red and green lights indicatewhether pedestrians may cross, accompanied by a countdown display.
(C) Red, yellow, and green lightsdisplay in sequence to instruct vehicles to stop, caution, or proceed.