If \[y={{\sin }^{-1}}\sqrt{1-{{x}^{2}}}\], then \[dy/dx=\] [AISSE 1987]

• A. \[\frac{1}{\sqrt{1-{{x}^{2}}}}\]
• B. \[\frac{1}{\sqrt{1+{{x}^{2}}}}\]
• C. \[-\frac{1}{\sqrt{1-{{x}^{2}}}}\]
• D. \[-\frac{1}{\sqrt{{{x}^{2}}-1}}\]