Answer:
A. It provides evidence in support of the thesis statement.
Step-by-step explanation:
Choice B isn't correct because you shouldn't be making a direct statement containing the thesis in the second paragraph of your essay. That's supposed to be done in the introductory paragraph.
Choice C isn't correct because you restate your thesis in the conclusion of your essay, not in the second paragraph.
Choice D isn't correct because the thesis statement shouldn't be a question, it should be a claim--and there shouldn't be questions in an essay, unless very well written and rhetorical.
Therefore, Choice A is correct. The body paragraph of an essay should always provide evidence to back up the essay's main claim/thesis.