Which sentence uses third person?

The sentence that uses third person is "She is reading a book." In this instance, the pronoun “she” refers to someone other than the speaker or the listener, which is the defining characteristic of third person. Third-person perspective is typically used to provide information about someone or something without involving the speaker (first person) or the audience (second person).

The other options involve either first person, with “I” expressing the speaker's own actions, or second person, which directly addresses the listener. This clarity differentiates third person from the other perspectives. In this case, the sentence about "she" clearly illustrates third-person usage by focusing solely on the individual outside the direct dialogue.