Factor; Then Use Fundamental Identities to Simplify the Expression Below $\csc ^ { 3 } x - \csc ^ { 2 } x - \csc x + 1$

Factor; then use fundamental identities to simplify the expression below and determine which of the following is not equivalent.

A) $\csc ^ { 3 } x - \csc ^ { 2 } x - \csc x + 1$
$\csc x \cot ^ { 2 } x - \cot ^ { 2 } x$

B) $\cos ^ { 2 } x \left( \frac { 1 - \sin x } { \sin ^ { 3 } x } \right)$

C) $\frac { \cos ^ { 4 } x } { \sin ^ { 3 } x + \sin ^ { 4 } x }$

D) $\frac { 1 - \sin x - \sin ^ { 2 } x + \sin ^ { 3 } x } { \sin ^ { 3 } x }$

E) $\frac { \sec ^ { 2 } x + \tan ^ { 2 } x } { \csc x }$