Explanation
Correct answer: C.
Choice C is the best answer because it most accurately describes the main idea of the text: a person appreciates the extensive time he passed in the company of a man he deeply admired. The speaker says that he spent "years" (a long period of time) in the company of a "truly great man" with "a natural genius for invention." These phrases indicate the speaker’s feelings of admiration.
Why the other choices are wrong
Choice A
Choice A is incorrect because though the text indicates that the speaker feels professional admiration for the "truly great man," the text does not indicate that the speaker feels love for him; nor does the text indicate that the speaker’s humility, absurdity, and slovenly nature proved to be an obstacle to this professional relationship.
Choice B
Choice B is incorrect because though the speaker describes himself as humble, the text does not indicate that he is exceptionally talented; nor does the text indicate that the "truly great man" professes humility or is concerned with whether he intimidates others.
Choice D
Choice D is incorrect because the text does not indicate how either the speaker or the "truly great man" express their ideas.