Phương trình 6 sin^2 x + 7 căn bậc hai của 3 sin 2x - 8 cos^2 x

A. $\left[\begin{array}{l}x=\frac{\pi }{2}+k\pi \\ x=\frac{\pi }{6}+k\pi \end{array}\right.(k\in Z)$

B. $\left[\begin{array}{l}x=\frac{\pi }{4}+k\pi \\ x=\frac{\pi }{3}+k\pi \end{array}\right.(k\in Z)$

C. $\left[\begin{array}{l}x=\frac{\pi }{8}+k2\pi \\ x=\frac{\pi }{12}+k2\pi \end{array}\right.(k\in Z)$

D. $\left[\begin{array}{l}x=\frac{\pi }{8}+k\pi \\ x=\frac{\pi }{12}+k\pi \end{array}\right.(k\in Z)$