Light Is Refracted Through a Diamond $\degree$ ,And the Angle of Refraction Is 12

Multiple Choice

Light is refracted through a diamond.If the angle of incidence is 30 $\degree$ ,and the angle of refraction is 12 $\degree$ ,what is the index of refraction?

A) 1.3
B) 2.4
C) 2.6
D) 1.8
E) 0.4