A rocket is going towards moon with a speed v. The astronaut in the rocket sends signals of frequency \[\nu \] towards the moon and receives them back on reflection from the moon. What will be the frequency of the signal received by the astronaut (Take v

• A.            \[\frac{c}{c-v}\nu \]          
• B.            \[\frac{c}{c-2v}\nu \]
• C.            \[\frac{2v}{c}\nu \]           
• D.            \[\frac{2c}{v}\nu \]