Sec. 1. This chapter applies to the following counties:
(1) A county having a population of more than forty-three thousand five hundred (43,500) and less than forty-five thousand (45,000).
(2) A county having a population of more than nineteen thousand eight hundred fifty (19,850) and less than twenty thousand (20,000).
(3) A county having a population of more than ten thousand (10,000) and less than twelve thousand (12,000).