The correct answer is C. Section.
A section is a part of a document that has its own unique formatting, such as page size, margins, and orientation. To print a report using letterhead, you need to create a new section and specify that the letterhead should be used for that section.
The other options are incorrect because they do not affect the formatting of a document as a whole. Group is a setting that controls how objects are grouped together in a document. Margin is a setting that controls the amount of space between the edge of the page and the text. Orientation is a setting that controls whether the page is printed in portrait or landscape mode.