A train moves towards a stationary observer with speed 34 m/s. The train sounds a whistle and its frequency registered by the observer is $$f_1$$. If the speed of the train is reduced to 17 m/s, the frequency registered is $$f_2$$. If speed of sound is 340 m/s, then the ratio $$f_1/f_2$$ is:

A

21/20

B

20/19

C

19/18

D

18/17