The integral $80\int_0^{\frac{\pi}{4}} \left(\frac{\sin\theta + \cos\theta}{9 + 16\sin 2\theta}\right)d\theta$ is equal to:\\ (1) $3\log_e 4$\\ (2) $4\log_e 3$\\ (3) $6\log_e 4$\\ (4) $2\log_e 3$