The integral $\int_0^{\pi/4} \frac{\sin x + \cos x}{9 + 16\sin 2x} dx$ is equal to:\\ (1) $\frac{1}{20} \log 3$\\ (2) $\log 3$\\ (3) $\frac{1}{20} \log 9$\\ (4) $\frac{1}{10} \log 3$