To finalize the direction of a survey, four surveyors set up a theodolite at a station $\mathrm{P}$ and performed all the temporary adjustments. From the station $\mathrm{P}$, each of the surveyors observed the bearing to a tower located at station $Q$ with the same instrument without shifting it. The bearings observed by the surveyors are $30^{\circ} 30^{\prime} 00^{\prime \prime}, 30^{\circ} 29^{\prime} 40^{\prime \prime}, 30^{\circ} 30^{\prime} 20^{\prime \prime}$ and $30^{\circ} 31^{\prime} 20^{\prime \prime}$. Assuming that each measurement is taken with equal precision, the most probable value of the bearing is
- $30^{\circ} 29^{\prime} 40^{\prime \prime}$
- $30^{\circ} 30^{\prime} 20^{\prime \prime}$
- $30^{\circ} 30^{\prime} 00^{\prime \prime}$
- $30^{\circ} 31^{\prime} 20^{\prime \prime}$