答案:A
解析:
Choice A is the best answer. Throughout the passage, Tocqueville argues that in the United States the people truly govern and have power, as he has seen that they participate in the selection of their authorities and in the creation and implementation of the laws. Tocqueville's argument would be weakened if, at the time he was writing, it were true that most people in the United States were not permitted to vote and therefore were not participants in the government.