Choose the correct answer $\sin (\tan^{-1}x), |x| <1 $ is equal to

Question

$(A)\;\frac{x}{\sqrt{1-x^2}} \\(B)\;\frac{1}{\sqrt{1-x^2}} \\(C)\;\frac{1}{\sqrt{1+x^2}} \\ (D)\;\frac{x}{\sqrt{1+x^2}}$