To solve this question, the user needs to understand the grammar rules for subject-verb agreement and pronoun usage. In this sentence, "uncle" is the subject, and the question is asking for the appropriate pronoun to refer to him.

The correct answer is:

B. he

Explanation: In the sentence, "uncle" is a singular third-person masculine noun, and the pronoun that refers to him must also be singular and masculine. "He" is the appropriate pronoun to use in this case. Option A ("it") is incorrect because "it" is used to refer to inanimate objects or animals, not people. Option C ("you") and option D ("me") are also incorrect because they are not appropriate pronouns to refer to the uncle.