Which type of communication is more formal?

• A. Email
• B. Memorandum for Record
• C. Official Memorandum
• D. Text message

Answer: (C)

Formal written communication in a military/public health operations context relies on documents that carry official weight and are preserved as part of the official record. An Official Memorandum uses a standardized format with a clear header, subject, body, and an authorized signature block, and it is issued by an official entity for formal directives, policies, or instructions. This structure and authority make it the most formal channel among common options, ensuring the message is treated as official guidance and retained as a formal record.

Emails can be formal, but they are typically more informal and less enduring as official records. A Memorandum for Record is used to document events or decisions for internal reference and may not have the same formal distribution or policy weight. Text messages are inherently quick, informal, and not suitable for formal directives or enduring records.