A Stationary Emitter Generates a Sound of Frequency $V$ the Frequency Shift

Multiple Choice

A stationary emitter generates a sound of frequency $V$ . The frequency shift $\delta v _ { \gamma }$ if the receiver is moving at a speed that is not < the speed of sound in still air is related to the frequency shift $\delta v _ { e }$ if the emitter moves at precisely the same speed (in the appropriate direction) with respect to a stationary receiver by the relation

A) $V _ { y } > V _ { e }$
B) $V _ { y } = V _ { e }$
C) $V _ { y } < V _ { e }$
D) none of the above.