JEE Math Practice Question

Let $$A = \left( {\begin{matrix} {\cos \alpha } & { - \sin \alpha } \\ {\sin \alpha } & {\cos \alpha } \\ \end{matrix} } \right)$$, ($$\alpha $$ $$ \in $$ R) such that $${A^{32}} = \left( {\begin{matrix} 0 & { - 1} \\ 1 & 0 \\ \end{matrix} } \right)$$ then a value of $$\alpha $$ is

1. A.0
2. B.$${\pi \over {16}}$$
3. C.$${\pi \over {32}}$$
4. D.$${\pi \over {64}}$$