Which statement regarding a memo is true?

A memo is designed to convey information succinctly and efficiently, making it important to focus solely on essential information. This approach allows the recipient to grasp the key message quickly and reduces the potential for misunderstandings. By concentrating on what's necessary, a memo avoids unnecessary details that could detract from the main point, ensuring clear communication.

The other aspects mentioned, such as making a main point multiple times, the use of an authoritative format, and avoiding headings, do not capture the fundamental purpose of a memo. A memo generally aims for clarity and brevity, emphasizing the key information without repetition or excessive formalities. Thus, the inclusion of only essential information is the hallmark of effective memo writing.