The sentence that best supports the idea that the paragraph belongs in the middle of Sora's essay is the first one: That day after practice, I was frustrated and stomped home.
This sentence, the one that introduces the paragraph, is making a direct reference to something that has happened before in the story, which Sora has probably already told the reader about. When she uses the relative pronoun "that", it can be understood that Sora was already talking about that day before, and also the word "practice" is already referring to an information she must have given before in her essay. Just by what is said in the first sentece the reader can't understand what she was practicing. Moreover, when Sora says that she was frustrated, the reader can't understand her reasons, which must have been explained before in her narrative. Therefore, the correct answer to which sentence best supports the idea that this paragraph belongs in the middle of Sora's essay is the first one: That day after practice, I was frustrated and stomped home.
The other options couldn't be correct, because all of the other sentences refer to something said before in the same paragraph. When analyzing the other options, it can be understood that all of the references made to what has already been said are within the same paragraph. The following information can be comprehended by the reader without the need of any extra information apart from the paragraph given.