$$y = \tan^{-1}\left(\frac{x^2}{2}\right)$$ what is $$\frac{dy}{dx}$$?

A

$$\frac{4x}{(4 + x)}$$

B

$$\frac{4}{(4 + x^2)}$$

C

$$\frac{x}{(4 + x^2)}$$

D

$$\frac{4x}{(4 + x^2)}$$