Perform the Indicated Operations and Simplify the Result $$\frac { \frac { 3 } { x ^ { 2 } - 4 x - 21 } - \frac { 1 } { x - 7 } } { \frac { 1 } { x + 3 } + 1 }$$

Multiple Choice

Perform the indicated operations and simplify the result. Leave the answer in factored form.
- $$\frac { \frac { 3 } { x ^ { 2 } - 4 x - 21 } - \frac { 1 } { x - 7 } } { \frac { 1 } { x + 3 } + 1 }$$

A) $\frac { x } { x ^ { 2 } - 5 x - 28 }$
B) $- 1$
C) $= \frac { x } { x ^ { 2 } - 3 x - 28 }$
D) $- \frac { x } { x ^ { 2 } - 4 x - 21 }$