Which of the following is considered a Package Service?

Media Mail is classified as a Package Service because it is specifically designed for mailing educational materials, such as books and educational media at a more affordable rate compared to other service types. This service offers a cost-effective way for individuals and businesses to send bulk items that qualify under its regulations, which ensures that it is primarily used for the shipment of materials that have intrinsic value for educational purposes.

In contrast, First-Class Mail is intended for letters and postcards, Priority Mail is a faster service for parcels, and Express Mail offers overnight delivery. Therefore, while all options represent ways to send mail, Media Mail uniquely serves a specific niche for educational content, thus categorizing it as a Package Service.