Answer:
A is glass, B is air, and C is water
Step-by-step explanation:
n_air < n_water < n_glass
This makes sense, since solids are denser than liquids, and liquids are denser than gases. Refractive index generally increases with density.
Snell's law states:
n₁ sin θ₁ = n₂ sin θ₂
What this means is the higher the index of refraction n, the lower the angle of incidence θ.
Media A has an angle of incidence of 15°.
Media B has an angle of incidence of 26°.
Media C has an angle of incidence of 21°.
Therefore, A is glass, B is air, and C is water.