(c)
Since, $\sin^{- 1}{\left( x\sqrt{1 - x} + \sqrt{x}\sqrt{1 - x^{2}} \right) = \sin^{- 1}{x + \sin^{- 1}\sqrt{x}}}$
$\therefore\ \ \ \ \ \frac{d}{dx}\{\sin^{- 1}{(x\sqrt{1 - x} + \sqrt{x}\sqrt{1 - x^{2}})\}}$
$= \frac{d}{dx}(\sin^{- 1}{x + \sin^{- 1}{\sqrt{x}) = \frac{1}{\sqrt{1 - x^{2}}} + \frac{1}{2\sqrt{x}\sqrt{1 - x}}}}$