I think this makes sense and I agree that A is the best answer. However, I think that the analogy is not completely satisfactory, since a traffic light stops the movement of the car, whereas in a solar eclipse, the Moon is blocking the signal (i.e. light) emitted by the Sun and does not influence the Sun's movement. Based on this, can you modify either the question or the answers such that the best answer results in an even more appropriate analogy?