$y= \log \bigg \{ \bigg (\large\frac{1+x}{1-x}\bigg )^{1/4}\bigg\}-\frac{1}{2}$$ \tan ^{-1}(x),$ then $\large\frac{dy}{dx}$ is equal to

Question

\[\begin {array} {1 1} (a)\;\frac{x}{1-x^2} & \quad (b)\;\frac{x^2}{1-x^4} \\ (c)\;\frac{x}{1+x^4} & \quad (d)\;\frac{x}{1-x^4} \end {array}\]