Find the Derivative of the Function $$r = \left( \frac { 1 + 7 \theta } { 7 \theta } \right) ( 7 - \theta )$$

Multiple Choice

Find the derivative of the function.
- $$r = \left( \frac { 1 + 7 \theta } { 7 \theta } \right) ( 7 - \theta )$$

A) $\frac { \mathrm { dr } } { \mathrm { d } \theta } = \frac { 1 } { \theta ^ { 2 } } + 1$
B) $\frac { d r } { d \theta } = \frac { 1 } { \theta ^ { 2 } } + 7$
C) $\frac { d r } { d \theta } = \theta ^ { 2 } - 1$
D) $\frac { d r } { d \theta } = - \frac { 1 } { \theta ^ { 2 } } - 1$