Choice A is the best answer. Throughout the passage, Smith poses questions that aren't answered explicitly until the last paragraph, but the leading tone of the speech makes it clear that the implied answer to these questions is "no." In the second paragraph, Smith questions her critics' claim that upholding humanitarian values undermines conventional feminine virtues. In the third paragraph, she wonders how women can "have no interest" in the subject of slavery when it could lead to the destruction of their families through war. In the last paragraph, she asks women numerous questions and then answers them with a "no." Thus, a technique that Smith uses throughout the passage to advance her main point is to present her claims in the form of rhetorical questions that mostly have implicit negative answers.
Choice B is incorrect. Although Smith questions the assertions that her opponents made, she doesn't criticize her opponents themselves by quoting self-contradictory remarks they have made. Choice C is incorrect. Although Smith makes use of vivid language and imagery throughout the passage, she doesn't illustrate each of her central ideas with an emotionally powerful anecdote. Choice D is incorrect. Although it is implied that Smith considers her views to be reasonable, she doesn't present them as universally held.