Tích phân \(J = \int\limits_{\frac{\pi }{6}}^{\frac{\pi }{4}} {c{\rm{os}}\left( {2x - \frac{\pi }{6}} \right)dx} \) bằng

A. \(\frac{{2\sqrt 3  + 1}}{4}\)

B. \(\frac{{\sqrt 3  - 1}}{4}\)

C. \(\frac{{\sqrt 3  + 1}}{4}\)

D. \(\frac{{2\sqrt 3  - 1}}{4}\)