During a firework show, a family sees the spray of sparkles from an exploding firework high in the sky and, a moment later, hears the pop. Which of these best explains why the pop and spray do not seem to occur at the same time?
a. Light and sound travel through air.
b. Sound travels through a vacuum.
c. Sound travels slower than light.
d. Light and sound travel at the same speed

c. Sound travels slower than light.

Explanation:

We see any thing because of the light emitted or reflected by it. Whereas the sound is carried by the sound waves. The speed of light is more than the speed of sound. This is the reason the family saw the fireworks first and then heard the sound.

The same can be experienced during the sighting of a Jet plane or a rocket where, we see them way before we can hear the roaring sound of its engines.