Consider the following complex numbers: $$z_1 = r_1(\cos \theta_1 + i \sin \theta_1)$$ $$z_2 = r_2(\cos \theta_2 + i \sin \theta_2)$$ where $r_1, r_2$ are real numbers, $0 \leq \theta_1 \leq \frac{\pi}{2}$, $0 \leq \theta_2 \leq \frac{\pi}{2}$, and $i = \sqrt{-1}$. If $|z_1 + z_2| = |z_1| + |z_2|$, which one of the following conditions is necessarily CORRECT?