Diffraction Grating: a Diffraction Grating Has Rulings of 890 Lines/mm

Multiple Choice

Diffraction grating: A diffraction grating has rulings of 890 lines/mm. When white light is incident normally on the grating, what is the longest wavelength that forms an intensity maximum in the fifth order?

A) 225 nm
B) 200 nm
C) 250 nm
D) 275 nm
E) 300 nm