JEE Math Practice Question

The domain of the function $${\cos ^{ - 1}}\left( {{{2{{\sin }^{ - 1}}\left( {{1 \over {4{x^2} - 1}}} \right)} \over \pi }} \right)$$ is :

1. A.$$R - \left\{ { - {1 \over 2},{1 \over 2}} \right\}$$
2. B.$$( - \infty , - 1] \cup [1,\infty ) \cup \{ 0\} $$
3. C.$$\left( { - \infty ,{{ - 1} \over 2}} \right) \cup \left( {{1 \over 2},\infty } \right) \cup \{ 0\} $$
4. D.$$\left( { - \infty ,{{ - 1} \over {\sqrt 2 }}} \right] \cup \left[ {{1 \over {\sqrt 2 }},\infty } \right) \cup \{ 0\} $$