When Light in Material 1, Which Is in Contact with Material

Multiple Choice

When light in material 1, which is in contact with material 2, undergoes total internal reflection, what condition is necessary for their indices of refraction?

A) n₁ = 2 n₂
B) n₁ > n₂
C) n₁ < n₂
D) n₁ = n₂ + 1
E) n₂ = 1.5