$$\int \frac{dx}{\cos x + \sqrt{3} \sin x}$$ equals

A

$$\frac{1}{2} \log \tan\left(\frac{x}{2} + \frac{\pi}{12}\right) + c$$

B

$$\frac{1}{2} \log \tan\left(\frac{x}{2} - \frac{\pi}{12}\right) + c$$

C

$$\log \tan\left(\frac{x}{2} + \frac{\pi}{12}\right) + c$$

D

$$\log \tan\left(\frac{x}{2} - \frac{\pi}{12}\right) + c$$