Use the Derivative Of $f ( x ) = 2 x ^ { 3 } + 6 x$

Multiple Choice

Use the derivative of $f ( x ) = 2 x ^ { 3 } + 6 x$ to determine any points on the graph of $f ( x )$ at which the tangent line is horizontal.

A) $( 1,8 )$
B) $( 1,8 )$ and $( - 1 , - 8 )$
C) $f ( x )$ has no points with a horizontal tangent line.
D) $( 2,28 )$ and $( - 2,28 )$
E) $( 0,0 )$