The direct and reversed zenith angles observed by a theodolite are $56^{\circ} 00^{\prime} 00^{\prime \prime}$ and $303^{\circ} 00^{\prime} 00^{\prime \prime}$, respectively. What is the vertical collimation correction?
- $+1^{\circ} 00^{\prime} 00^{\prime \prime}$
- $-1^{\circ} 00^{\prime} 00^{\prime \prime}$
- $-0^{\circ} 30^{\prime} 00^{\prime \prime}$
- $+0^{\circ} 30^{\prime} 00^{\prime \prime}$