If $y=\left(1-x^2\right) \operatorname{Tanh}^{-1} x$ then $\frac{d^2 y}{d x^2}=$

• A

  $\frac{2 x y}{\left(1+x^2\right)^2}$
• B

  $-\frac{(x+y)}{\left(1-x^2\right)^2}$
• C

  $\frac{2(x y)}{1-x^2}$
• Correct answer
  D

  $-\frac{2(x+y)}{1-x^2}$

Hence, the correct answer is option: 'D'.