The point on the curve

Given that the curve $y=12 x-x^{2}$

The slope of the curve $\frac{d y}{d x}=12-2 x$

Given that the slope of the tangent $=0$

$\Rightarrow 12-2 x=0$

$\Rightarrow x=6$

So, $y=72-36$

$\Rightarrow y=36$

So, the correct option is $D$.