Political scientist: People become unenthusiastic about voting if they ... ...

Political scientist: People become unenthusiastic about voting if they believe that important problems can be addressed only by large numbers of people drastically changing their attitudes and that such attitudinal changes generally do not result from government action. The decreasing voter turnout is thus entirely due to a growing conviction that politicians cannot solve the most important problems. The reasoning in the political scientist’s argument is most vulnerable to criticism on the grounds that the argument
(A) presumes, without providing justification, that there is no cause of decreasing voter turnout other than the belief that few important problems can be solved by government action
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Dec 2012 LSAT (PT68): Logical Reasoning B