Factor; Then Use Fundamental Identities to Simplify the Expression Below $\cot ^ { 2 } \alpha - \cot ^ { 2 } \alpha \cos ^ { 2 } \alpha$

Factor; then use fundamental identities to simplify the expression below and determine which of the following is not equivalent. $\cot ^ { 2 } \alpha - \cot ^ { 2 } \alpha \cos ^ { 2 } \alpha$

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