I'm pretty sure the answer would be sentence number 8
Explanation:
This is the start of a new paragraph, and it uses the pronoun "they" for Noel and his friend. The reader might forget who "they" is by this point. In the next sentence the author uses "they" again. It's not exactly precise to use they twice in a row like that because again, the reader might forget who they is referring to. Sentence 8 should say Hami and Noel, instead of they, and then it would be perfectly fine to use they in the next sentence.
