Multiply; Then Use Fundamental Identities to Simplify the Expression Below $( \sin x + \cos x ) ( \sin x - \cos x )$

Multiply; then use fundamental identities to simplify the expression below and determine which of the following is not equivalent.
$( \sin x + \cos x ) ( \sin x - \cos x )$

A) $2 \sin ^ { 2 } x - \sec ^ { 2 } x - \tan ^ { 2 } x$
B) $\sin ^ { 2 } x - \cos ^ { 2 } x$
C) $1 - 2 \cos ^ { 2 } x$
D) $\csc ^ { 2 } x - \cot ^ { 2 } x - 2 \cos ^ { 2 } x$
E) $1 - 2 \sin \left( \frac { \pi } { 2 } - x \right) \cos x$