The solutions of the equation $\left| {\matrix{ {1 + {{\sin }^2}x} & {{{\sin }^2}x} & {{{\sin }^2}x} \cr {{{\cos }^2}x} & {1 + {{\cos }^2}x} & {{{\cos }^2}x} \cr {4\sin 2x} & {4\sin 2x} & {1 + 4\sin 2x} \cr } } \right| = 0,(0 < x < \pi )$, are
1${\pi \over {12}},{\pi \over 6}$
2${\pi \over {6}},{\pi \over 6}$
3${5\pi \over {12}},{7\pi \over 12}$
4${7\pi \over {12}},{11\pi \over 12}$