Choice C is the best answer. When, in the eighth paragraph, the narrator asks Sempere if the author Charles Dickens is a friend of his, Sempere replies, in the ninth paragraph, that Dickens is a "lifelong friend. And from now on, he's your friend too." Sempere designated Dickens a "friend" of both himself and the narrator, who had never heard of the author before. This signals that the use of "friend"in these lines is figurative and emphasizes Sempere's emotional connection to Dickens and, more generally, to reading. It also signals Sempere's hope that the narrator will come to have a similar connection to Dickens.
Choices A, B, and D are incorrect because the word "friend" is used in these lines to emphasize Sempere's connection to reading, rather than his connection to the narrator (choice A), the narrator's relationships or home life (choice B), or the narrator's emotional state or decision making (choice D).