Why is C correct? Why is A incorrect?

@Ryan-Mahabir, (C) is correct because the advocate argues that public funding of campaigns will result in (a) politicians spending less time campaigning (b) caps on individual campaign contributions. The critic points out that putting a cap on individual campaign contributions will actually result in politicians spending more time seeking small donors, thus the proposal results in two contradictory results -> spend more time on the fund-raising vs. spend less time on the fundraising. (A) is incorrect because the critic is arguing that a cap together with public funding will read to an absurd result not that it can be easily circumvented as (A) suggests.

@Irina Would you please explain a little more? I still don't understand the reasoning behind this answer.

The author says there are two good things: that candidates spend less time fundraising, and that they will be less beholden to individuals. The critic points out that by doing one, the other gets harder. By capping individual donations, they have to spend more time fundraising.