A Diver,below the Surface of a Lake,notices That No Light $\theta$

Multiple Choice

A diver,below the surface of a lake,notices that no light appears to be coming toward her greater than the angle $\theta$ ,measured from the vertical.If the index of refraction of water is 1.33,what is the angle $\theta$ ?

A) 30 $^{\circ}$
B) 34 $^{\circ}$
C) 37 $^{\circ}$
D) 49 $^{\circ}$
E) 54 $^{\circ}$