Which of the following sentences uses the correct homophone?

The sentence "I want to go there after school" uses the correct homophone. The word "there" in this context indicates a place or location, which is the intended meaning. In contrast, the other sentences either use incorrect forms or do not include a homophone error. For instance, in the sentence about the number of people in the room, the word "too" correctly refers to excess, rather than using "to," which indicates direction. Similarly, the other choices misuse the word "they are," which is a contraction of "they are" instead of the intended term, "their," which indicates possession. Thus, the sentence that accurately employs the correct homophone is the one stating the desire to go to a specified location.