我觉得应该是C,因为
Logical argument is the plot, as it were, of any speech or essay that is respectfully intended to persuade people. Yet it is a characterizing feature of rhetoric that it goes beyond this and appeals to the parts of our nature that are involved in feeling, desiring, acting, and suffering.
说明了修辞比逻辑有更多的内容,所以B中的only有问题。C没有什么错误的地方。