For the Given Functions F and G , Find the Indicated

Multiple Choice

For the given functions f and g , find the indicated composition.
- $$\begin{array} { l } f ( x ) = \sqrt { x - 1 } , \quad g ( x ) = - \frac { 7 } { x } \\( g f ) ( x ) \end{array}$$

A) $\sqrt { - \frac { 7 } { x } - 1 }$

B) $- \frac { 1 } { \sqrt { 7 x - 1 } }$

C) $\frac { 7 } { \sqrt { - x - 1 } }$

D) $- \frac { 7 } { \sqrt { x - 1 } }$