Which element is included in a formal memo header only if applicable?

• A. Reference (if applicable)
• B. Date
• C. To/From
• D. Subject

Answer: (A)

In a formal memo header, only items that actually apply are included. The Reference line is used to point to a prior document, directive, or memo, so it should appear only when there is something to reference. When no previous document needs to be cited, this line is omitted to keep the header concise and focused. By contrast, elements like To, From, Date, and Subject are routinely present because they provide essential routing, identification, and topic information for the memo. So the Reference line is included only if there is a relevant reference to cite.