The function $y = e ^ { k x }$ satisfies
$$\left( \frac { d ^ { 2 } y } { d x ^ { 2 } } + \frac { d y } { d x } \right) \left( \frac { d y } { d x } - y \right) = y \frac { d y } { d x }$$
for\\
(A) exactly one value of $k$.\\
(B) two distinct values of $k$.\\
(C) three distinct values of $k$.\\
(D) infinitely many values of $k$.