Final answer:
The subject of this question is English and the grade is Middle School. The sentence contains the indefinite pronoun 'no one', which makes it an indefinite pronoun question. The correct answer is 'b. indefinite'.
Step-by-step explanation:
The sentence 'After the summer, no one was ready to go back to school.' contains the indefinite pronoun 'no one'. Indefinite pronouns are general and do not refer to a specific person, place, or thing. In this sentence, 'no one' is referring to an unspecified person. Therefore, the correct answer is b. indefinite.
Learn more about Indefinite Pronouns