A Light Ray in Air Strikes a Glass Surface with an Angle

Multiple Choice

A light ray in air strikes a glass surface with an angle of incidence of 30.0 $^{\circ}$ .The angle of refraction in the glass is 20.0 $^{\circ}$ .What is the speed of light in the glass?

A) 3.00 $\times$ 10⁸ m/s
B) 2.50 $\times$ 10⁸ m/s
C) 2.33 $\times$ 10⁸ m/s
D) 2.05 $\times$ 10⁸ m/s
E) 1.50 $\times$ 10⁸ m/s