When is the Doppler Effect perceived by a person?
A. When a moving car has a higher pitch coming towards you and a higher pitch when it passes you.
B. When a moving car has a higher pitch coming towards you and a lower pitch when it passes you.
C. When a moving car has a lower pitch coming towards you and a higher pitch when it passes you.
D. When a moving car has a lower pitch coming towards you and a lower pitch when it passes you.
