As You Stand by the Side of the Road,a Car

Multiple Choice

As you stand by the side of the road,a car approaches you at a constant speed,sounding its horn,and you hear a frequency of 76 Hz.After the car goes by,you hear a frequency of 65 Hz.What is the speed of the car? The speed of sound in the air is 343 m/s.

A) 26 m/s
B) 27 m/s
C) 28 m/s
D) 29 m/s
E) 30 m/s