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. $f ( x ) = x ^ { 3 } , \quad ( 2,8 )$

A) $m = - 3 x ^ { 2 }$
At $( 2,8 ) , m = 12$
B) $m = - 3 x ^ { 2 }$
At $( 2,8 ) , m = - 12$
C) $\begin{array} { l } m = x ^ { 2 } \\\text { At } ( 2,8 ) , m = 6\end{array}$
D) $m = 3 x$
At $( 2,8 ) , m = 6$
E) $m = 3 x ^ { 2 }$
At $( 2,8 ) , m = 12$