A method for electing the governing body of a county or municipal corporation may not be imposed or applied in a manner that impairs the ability of members of a protected class to elect candidates of the members’ choice or the members’ ability to influence the outcome of an election as a result of the dilution or the abridgement of the rights of voters who are members of a protected class. A violation of subsection (a) of this section is established if: elections in a county or municipal corporation exhibit polarized voting; and the method of election dilutes or abridges the voting strength of members of a protected class to elect a candidate of the members’ choice or the members’ ability to influence the outcome of an election, as demonstrated by the existence of one or more methods of election that could be constitutionally adopted that would likely mitigate the dilution.