C. Any county having a population of at least one hundred fifty thousand persons but not more than one hundred seventy-five thousand persons and having a county board of supervisors that consists of three persons shall submit to the electors in the county, at the next general election after the release of the population estimate from the office of economic opportunity, the question of whether the county shall elect five members to the board of supervisors. The ballots must contain the words: "Five supervisors, yes. Five supervisors, no." If approved by a majority of the qualified electors of that county who voted on the question, the board of supervisors shall redistrict the county pursuant to section 11-212. The county thereafter shall elect at the next general election immediately following the election at which the question is approved the prescribed number of members to the board of supervisors who shall have the same qualifications as provided in subsection A of this section. The following apply to the election for the county board of supervisors prescribed in this subsection:

1. 1. If the next general election immediately following the election at which the question is approved is held in a year that is the last year of the four-year term of the three members of the county board of supervisors who are already holding office, the five persons elected to the county board of supervisors hold office for a term of four years to commence on January 1 immediately following their election.
2. 2. If the next general election immediately following the election at which the question is approved is held in a year that is not the last year of the four-year term of the three members of the county board of supervisors who are already holding office, the two additional persons elected to the county board of supervisors hold office for a term of four years to commence on January 1 immediately following their election. The three members of the county board of supervisors who are already holding office continue to serve their four-year terms of office without regard to whether they are residents of the newly redrawn supervisorial districts for the remainder of those four-year terms. Thereafter, members of the board of supervisors must be residents of their supervisorial district and the term of office for members of that county board of supervisors shall be staggered four-year terms.
3. 3. For the election at which the question of whether the county shall elect five members to the board of supervisors is on the ballot, the county shall include in the publicity pamphlet an estimate of the cost to the county for each additional member to the board of supervisors.
4. 4. For the purposes of this subsection, "population" means the population according to the annual population estimate provided by the office of economic opportunity.