Find the Slope of the Curve at the Indicated Point $$f ( x ) = 5 x ^ { 2 } + 2 x - 4$$

Multiple Choice

Find the slope of the curve at the indicated point.
-Find the points where the graph of the function have horizontal tangents.
$$f ( x ) = 5 x ^ { 2 } + 2 x - 4$$

A) $\left( \frac { 1 } { 5 } , - 10 \right)$
B) $\left( - \frac { 1 } { 5 } , - \frac { 21 } { 5 } \right)$
C) $( 0,4 )$
D) $( - 12,1472 )$