Answer:
A) light.
If sound and Light travel from point A to point B and start at the same time, Light will always reach point B first.
Explanation:
Sound is a longitudinal wave. It is simply the movement of particles in a medium. It can not travel through vacuum Its speed is 343 m/s in air.
Whereas, light is a transverse wave which can travel through a medium or through vacuum. Its speed is 3*10^8 m/s.
Although Sound travels faster in dense mediums, for instance, it is 14 times faster in iron than in air. And in case of light, although its speed is always constant but it takes time while in dense medium. The extra time comes when atoms absorb light and re-emit it in the same direction.
But still the difference is so big that Sound's speed can never reach light unless we discover a medium with infinite density.
