A：$(k\pi -\frac{\pi }{4},k\pi \left(k\in Z\right)$

B：$(k\pi -\frac{\pi }{8},k\pi +\frac{\pi }{8}\left(k\in Z\right)$

C：$(k\pi -\frac{3}{8}\pi ,k\pi +\frac{\pi }{8}\left(k\in Z\right)$

D：$(k\pi +\frac{\pi }{8},k\pi +\frac{3}{8}\pi \left(k\in Z\right)$