Final answer:
The sentence that uses appropriate tone and choice of words for a letter written to the principal of a school is option c: "All of us who live close to home should be allowed to leave campus for lunch so that we can get food and work harder in the afternoon."
Step-by-step explanation:
The sentence that uses appropriate tone and choice of words for a letter written to the principal of a school is:
c) "All of us who live close to home should be allowed to leave campus for lunch so that we can get food and work harder in the afternoon."
This sentence is polite and respectful, clearly stating the request to leave campus for lunch while also explaining the reason behind it. It uses formal language and presents a logical argument in a professional tone.