Light Reflected Off a Plate-Glass Window (N = 1 $\theta$ Find $\theta$

Multiple Choice

Light reflected off a plate-glass window (n = 1.5) is found to be completely polarised at angle-of-incidence $\theta$ .Find $\theta$ .

A) 56.3 $\degree$
B) 5.7 $\degree$
C) 21.2 $\degree$
D) 18.6 $\degree$
E) 33.7 $\degree$