Final answer:
Priority Mail is the correct answer to the question, providing two-to three-day service to most domestic destinations for packages weighing less than 70 pounds.
Step-by-step explanation:
The type of mail service that offers two-to three-day delivery to most domestic destinations and must weigh less than 70 pounds is Priority Mail (Option D). This service provided by the United States Postal Service (USPS) is designed for packages that require expedited delivery without the premium price of express services. It is a convenient option for sending gifts, business documents, or any other items that need to reach their destination within a short time frame.
It is important to mention that for Jesse, who works in the mailroom and needs to determine the correct postage for a package containing books and documents, the metric system is useful as it allows for precise weight measurements. He should use the metric unit of mass, such as grams or kilograms, to weigh the package.