Three Flat Layers of Transparent Material Are Stacked Upon One

Multiple Choice

Three flat layers of transparent material are stacked upon one another.The top layer has index of refraction n₁,the middle n₂ and the bottom one n₃.If n₁ > n₂ > n₃,and a ray of light in air strikes the top layer,at which surface given can total internal reflection occur first?

A) the top surface
B) the surface between materials with indices n₁ and n₂
C) the surface between materials with indices n₂ and n₃
D) Total internal reflection cannot occur at any of these surfaces.