Due to Doppler effect, the shift in wavelength observed is $$0.1 A^\circ$$, for a star producing a wavelength $$6000 A^\circ$$. The velocity of recession of the star will be:

A

$$20 km s^{-1}$$

B

$$2.5 km s^{-1}$$

C

$$10 km s^{-1}$$

D

$$5 km s^{-1}$$