What are the maximum dimensions for letter-size mail?

The correct answer is based on the established dimensions for letter-size mail as defined by postal standards. The maximum dimensions for letter-size mail are a height of 6 ⅛ inches, a length of 11 ½ inches, and a thickness of ¼ inch.

This specification is important because it outlines the limits for mail that can be sent at a letter rate, ensuring that the mail fits the guidelines for automated processing in postal systems. Adhering to these dimensions allows for efficient handling and reduces the likelihood of additional handling fees or restrictions.

Other options present dimensions that exceed the maximum thickness limit or the length. The thickness in option B, which is ¼ inch, is compliant with postal regulations, making it the correct choice.