If $\theta$ and $\phi$ are acute angles satisfying $\sin \theta = \frac{1}{2}$ and $\cos \phi = \frac{1}{3}$,then $\theta + \phi \in$

• A
  $\left( \frac{\pi}{3}, \frac{\pi}{2} \right)$
• B
  $\left( \frac{\pi}{2}, \frac{2\pi}{3} \right)$
• C
  $\left( \frac{2\pi}{3}, \frac{5\pi}{6} \right)$
• D
  $\left( \frac{5\pi}{6}, \pi \right)$