You Could Determine the Index of Refraction for Visible Light

Multiple Choice

You could determine the index of refraction for visible light of a dark but reflective medium such as black glass by measuring the:

A) angles of incidence and refraction.
B) angle of reflection for an arbitrary angle of incidence.
C) angle at which reflected light is completely polarised.
D) smallest angle at which X-ray diffraction occurs in the glass.
E) smallest angle at which diffraction occurs for visible light when a diffraction pattern is scratched onto the surface.