Determine All Values of , (If Any), at Which the Graph

Multiple Choice

Determine all values of , (if any) , at which the graph of the function has a horizontal tangent.
$y ( x ) = x ^ { 3 } + 12 x ^ { 2 } + 8$

A) $x = 0$
B) $x = - 8$
C) $x = 0$ and $x = - 8$
D) $x = 0$ and $x = 8$
E) The graph has no horizontal tangents.