The commission charged with the supervision of such school shall be three in number and shall hold their said offices for terms of three years and until their successors are appointed by the board of chosen freeholders. The commission shall annually report to the board of chosen freeholders. Vacancies occurring for any cause shall be filled by the board of chosen freeholders for the unexpired term.
Any person a resident of the county for a period of at least five years prior to the passage of this act may be selected to membership in such commission.