Evaluate the Following Expression $( 1 + \sin \alpha ) ( 1 - \sin \alpha )$

Multiple Choice

Evaluate the following expression. $( 1 + \sin \alpha ) ( 1 - \sin \alpha )$

A) $\cos ^ { 2 } \alpha$
B) $- \cos ^ { 2 } \alpha$
C) $- 2 \sin ^ { 2 } \alpha$
D) $2 \cos ^ { 2 } \alpha$
E) $\sin ^ { 2 } \alpha$