While You Are Standing on a Corner,a Police Car with a 1-KHz

Multiple Choice

While you are standing on a corner,a police car with a 1-kHz siren drives past you at 30 m/s with its siren on.The speed of sound is 340 m/s.After the car has passed,the frequency you hear is about

A) 1.10 kHz
B) 1.09 kHz
C) 1.00 kHz
D) 919 Hz
E) 912 Hz