Light travels from air into glass as shown below.

The refractive index of the glass is

A. $\frac{{\sin 30^\circ }}{{\sin 80^\circ }}$

B. $\frac{{\sin 80^\circ }}{{\sin 30^\circ }}$

C. $\frac{{\sin 60^\circ }}{{\sin 10^\circ }}$

D. $\frac{{\sin 10^\circ }}{{\sin 60^\circ }}$

C