The Index of Refraction for Diamond Is 2

Multiple Choice

The index of refraction for diamond is 2.5. Which of the following is correct for the situation shown?

A) (sin a) /(sin b) = 2.5
B) (sin b) /(sin d) = 2.5
C) (cos a) /(cos c) = 2.5
D) (sin a) /(sin c) = 1/(2.5)
E) a/c = 2.5