The answer is: C. Variations in font size are used to create emphasis.
Effective business documents must be concise and organized. First, the introduction must include who the document is aimed at and its purpose. Finally, the body must contain the information arranged in paragraphs or bulleted lists, with headings and subheadings where necessary.
The rest of the options are incorrect because business document titles are not meant to entertain but to inform, a small font size does not mean the information is more relevant, and there is no rule to indicate how many sentences paragraphs must possess.