Find a Formula for the Slope of the Graph Of f

Multiple Choice

Find a formula for the slope of the graph of $f$ at the point $( x , f ( x ) )$ .Then use it to find the slope at the given point. $f ( x ) = 6 - x ^ { 2 } , \quad ( 0,6 )$

A) $\begin{array} { l } m = 2 x \\\text { At } ( 0,6 ) , m = 0\end{array}$
B) $\begin{array} { l } m = - 2 x \\\text { At } ( 0,6 ) , m = 0\end{array}$
C) $\begin{array} { l } m = 37 x \\\text { At } ( 0,6 ) , m = 0\end{array}$
D) $\begin{array} { l } m = 12 x \\\text { At } ( 0,6 ) , m = 0\end{array}$
E) $\begin{array} { l } m = 6 x \\\text { At } ( 0,6 ) , m = 0\end{array}$