Find $\large \frac{dy}{dx}$ when x and y are connected by the relation $\tan^{-1}(x^2+y^2)=a$

$\begin{array}{1 1}(A)\;\large\frac{y}{x}\\(B)\;\large\frac{-y}{x}\\(C)\;\large\frac{x}{y}\\(D)\;\large\frac{-x}{y}\end{array}$

Toolbox:
• A function $f(x,y)$ is said to be implicit if it is jumbled in such a way,that it is not possible to write $y$ exclusively as a function of $x$.
• $\large\frac{d}{dx}$$\phi(y)=\large\frac{d}{dy}$$\phi(y).\large\frac{dy}{dx}$
$\tan^{-1}(x^2+y^2)$$=a Differentiating w.r.t x we get \large\frac{1}{1+(x^2+y^2)^2}$$.(2x+2y\large\frac{dy}{dx})=0$