Which of the following is a postal rate for First-Class Mail related to letters?

The correct option encompasses all the provided postal rates for First-Class Mail related to letters. First-Class Mail is a service that provides various rates for letters based on their weight and size.

The rates specified in the choices highlight the structure of fees for letters under First-Class Mail:

1. The rate for a 1-ounce letter is established at $0.470, which reflects the standard charge for the most common letter weight, ensuring affordable mailing for everyday correspondence.

2. The rate for a 2-ounce letter is set at $0.680, indicating that as the weight increases, so does the cost, consistent with postal rate programs designed to scale charges according to the services rendered.

3. Additionally, another rate of $0.245 for each piece reflects a potential bulk mailing or presort discount that could be applicable under specific circumstances.

By choosing "all of the above," it correctly acknowledges that each provided rate represents legitimate charges for mailing letters via First-Class Mail, illustrating the tiered pricing model utilized by postal services that vary based on weight and service level. Each rate is accurate and corresponds to how postal services categorize and charge for letter mail.