Find and Simplify the Difference Quotient of F $\frac { f ( x + h ) - f ( x ) } { h }$

Multiple Choice

Find and simplify the difference quotient of f $\frac { f ( x + h ) - f ( x ) } { h }$ , h ≠ 0, for the function.
- $( x ) = \frac { 1 } { 7 x }$

A) $\frac { - 1 } { x ( x + h ) }$
B) $\frac { 1 } { 7 x }$
C) 0
D) $\frac { - 1 } { 7 x ( x + h ) }$