The Critical Angle for Total Internal Reflection at a Diamond-Air $\theta$

Multiple Choice

The critical angle for total internal reflection at a diamond-air interface is 25°.Suppose light is incident at an angle of $\theta$ with the normal.Total internal reflection will occur if the incident medium is:

A) air and $\theta$ = 25°
B) air and $\theta$ > 25°
C) air and $\theta$ < 25°
D) diamond and $\theta$ < 25°
E) diamond and $\theta$ > 25°