The integral $\int\limits_{0}^{\pi} \frac{(x + 3) \sin x}{1 + 3\cos^2 x} dx$ is equal to:
$\frac{\pi}{3\sqrt{3}}(\pi + 6)$
$\frac{\pi}{\sqrt{3}}(\pi + 2)$
$\frac{\pi}{\sqrt{3}}(\pi + 1)$
$\frac{\pi}{2\sqrt{3}}(\pi + 4)$