Light of Wavelength 550 Nm Is Incident on a Diffraction

Multiple Choice

Light of wavelength 550 nm is incident on a diffraction grating that is 1 cm wide and has 1000 slits.What is the half-width of the m = 1 line?

A) 5.5 x 10^-5 rad
B) 5.5 x 10^-4 rad
C) 5.5 x 10^-3 rad
D) 5.5 x 10^-2 rad
E) 5.5 x 10^-1 rad