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

Multiple Choice

Determine all values of x, (if any) , at which the graph of the function has a horizontal tangent. $$y ( x ) = \frac { 6 x } { ( x - 9 ) ^ { 2 } }$$

A) $x = 9$ and $x = - 6$
B) $x = - 9$
C) $x = - 9$ and $x = 6$
D) $x = 6$
E) The graph has no horizontal tangents.