Which statement best distinguishes formal and informal communication?

• A. Casual tone is used in formal communication
• B. Letterhead is never used in formal documents
• C. Official documents printed on department letterhead are formal
• D. There is no difference between formal and informal communication

Answer: (C)

Formal communication is defined by official format and presentation, signaling that the message comes from and on behalf of an organization. The statement that official documents printed on department letterhead are formal perfectly captures this idea: letterhead identifies the source as formal and authoritative, and the document is produced through official channels. That combination—official source, structured presentation, and formal tone—distinguishes formal communication from informal, which tends to be casual, personal, and less officially documented.

Casual tone in formal communication isn’t accurate because formality requires a professional, restrained tone. The belief that letterhead is never used in formal documents is incorrect—letterhead is a common marker of formality, not something that would be avoided. And saying there’s no difference between formal and informal communication ignores clear distinctions in purpose, tone, and documentation.