The Instantaneous Rate of Change Of $f ( x ) = \sqrt { x } + 5$

Multiple Choice

The instantaneous rate of change of $f ( x ) = \sqrt { x } + 5$ at c = 9 is

A) $- \frac { 1 } { 6 }$
B) $- \frac { 1 } { 3 }$
C) $- \frac { 1 } { 2 }$
D) $\frac { 1 } { 6 }$
E) $\frac { 1 } { 3 }$