Choose the correct answer in $\int\limits_0^\frac{2}{3}\frac{dx}{4+9x^2}$ equals

Question

$\begin{array}{1 1}(A)\;\frac{\pi}{6} \\ (B)\;\frac{\pi}{12} \\ (C)\frac{\pi}{24} \\ (D)\frac{\pi}{4} \end{array}$