(a) "School district" means all of a school district or all of its territory.
(b) "Voting plan" means one of the three voting plans described in this act. "Voting plan-A" is election at large in both primary and general elections. "Voting plan-B" is voting by a district method in the primary and by election at large in the general election. "Voting plan-C" is voting by a district method in both the primary and general elections.