Why are you able to observe the Doppler effect on earth with sound waves but not with light waves?

When an ambulance passes with its siren blaring, you hear the pitch of the siren change: as it approaches, the siren’s pitch sounds higher than when it is moving away from you. This change is a common physical demonstration of the Doppler effect.

Explanation:

i think the answer is a, hope this is right, that would be my best guess.