Solve this following

Mark $(\sqrt{)}$ against the correct answer in the following:

$f(\mathrm{x})=[\mathrm{x}(\mathrm{x}-3)]^{2}$ is increasing in

A. $(0, \infty)$

B. $(-\infty, 0)$

C. $(1,3)$

D. $\left(0, \frac{3}{2}\right) \cup(3, \infty)$