The Earth orbits the Sun at a speed of 30 km/s. At that speed it completes one path around the Sun every year. Of course, as that happens we are heading toward a different place in space constantly, always accelerating toward the Sun to stay on the circular path. Suppose at a paritcular instant we are headed in the direction of a distant star and we measure the speed of the light from that star as it arrives on Earth. In the vacuum of space we would measurea. 299,792,458 m/sb. 299,792,428 m/sc. 299,792,488 m/sd. 0 m/s