If $$y = \sec^{-1} \left[\frac{(x + 1)}{(x - 1)}\right] + \sin^{-1} \left[\frac{(x - 1)}{(x + 1)}\right]$$ then $$\left(\frac{dy}{dx}\right)$$ is equal to:

A

0

B

$$\frac{\pi}{2}$$

C

1

D

None of these