The light with a wavelength of 500 nm is incident perpendicularly on the

diffraction grating. The distance between the central fringe and the first order

fringe is 20 cm. If the distance between the first order fringe and the diffraction

grating is 0.5 m, the diffraction grating constant is approximately:

A) 1 m

B) 1.25 m

C) 2.5 m

D) 5 m

E) 10 m