Explanation
Correct answer: C.
Choice C is the best answer because it most accurately describes how the underlined sentence functions in the text as a whole. The underlined sentence establishes a difference between Uncle Katsuhisa and the narrator’s father by describing Uncle Katsuhisa as "loud" and the narrator’s father as "quiet." The text then elaborates on that contrast, describing some ways Uncle Katsuhisa is very noisy even when he isn’t speaking.
Why the other choices are wrong
Choice A
Choice A is incorrect because the text doesn’t indicate what kinds of topics Uncle Katsuhisa enjoys discussing, only that he is loud even when he isn’t speaking.
Choice B
Choice B is incorrect because the text never indicates how Uncle Katsuhisa feels about meeting new people, only how loud he is.
Choice D
Choice D is incorrect because the text never describes a conversation occurring between any people; it refers to talking only when stating that Uncle Katsuhisa is loud even when he isn’t speaking.