Light travels from air into glass as shown below.

What is the refractive index of glass?

A. \(\frac{{\sin P}}{{\sin S}}\)

B. \(\frac{{\sin Q}}{{\sin R}}\)

C. \(\frac{{\sin P}}{{\sin R}}\)

D. \(\frac{{\sin Q}}{{\sin S}}\)

D