The correct answer is:
A. Voters believe their votes will have no impact in an election.
Political efficacy refers to the sense of how effective someone´s vote will actually have an influence on the political process. It´s the position a voter can have about how much his vote really matters. A high sense of political efficacy could lead us to conclude that our vote will definitely make a difference. On the other side, a low sense of political efficacy would make us think there´s not enough power in that vote.