Find the Partial Fraction Decomposition for the Rational Expression $\frac { 21 x ^ { 2 } - 3 x ^ { 3 } } { x ^ { 2 } ( 7 - x ) }$

Multiple Choice

Find the partial fraction decomposition for the rational expression.
- $\frac { 21 x ^ { 2 } - 3 x ^ { 3 } } { x ^ { 2 } ( 7 - x ) }$

A) 7
B) $- 7$
C) $- 3$
D) 3