Hàm số \(y = \tan \left( { \frac{x}{3} + \frac{ \pi }{6}} \right) \) xác định khi:
A.\(x \ne \pi + k3\pi ,\left( {k \in Z} \right)\).
B.\(x \ne - \frac{\pi }{{12}} + k3\pi ,\left( {k \in Z} \right)\).
C. \(x \ne - \frac{\pi }{2} + k6\pi ,\left( {k \in Z} \right)\).
D. \(x \ne \pi + k6\pi ,\left( {k \in Z} \right)\).