A diffraction grating commonly

Question

A. produces multiple reflections.
B. converges light of different colors.
C. disperses light into its component colors.
D. spreads light according to amplitude.

Answer 1

This is sort of a textbook definition question, and there is really no way to approach it without just saying what a diffraction grating does.  Have you seen a diffraction grating in action (or seen pictures or videos of one)?  How would you describe what it does?