True or False: All business letters must include a subject line.

Business letters do not necessarily require a subject line. While including a subject line can enhance clarity and provide a quick reference point for the reader about the contents of the letter, it is not a strict requirement for all types of business correspondence. Many letters, particularly more informal ones or those without a specific subject that needs emphasis, can effectively communicate without a designated subject line.

The absence of a subject line may be appropriate in situations where the purpose of the letter is clear through the content, or when the letter is part of a continual correspondence where the context is understood. Thus, stating that all business letters must include a subject line is inaccurate, supporting the assertion that it is false.