Showing that Sergei considers the goldfish to be his friend, there does not seem to be a conflict with the relationship between the two. And, yes. It can be called a friendship because any two living organisms can be friends if there wanted to.
The correct answer is D, because that is the only appropriate shift in tense. A isn't correct because present perfect tense (have raced) is used inappropriately, when it should have been past perfect. B is also incorrect because past perfect means that that action happened before the storm blew, which is not the case. C features future continuous tense, which is impossible due to shift in tense. Therefore, the answer is D, because there is an appropriate tense in that sentence, past simple.
