What information is contained in line eight of a message?

Line eight of a message is used to indicate the distribution list for the message, specifically detailing who is to receive the information included in the message. This includes recipients who are copied, often referred to as "info" or "CC" (carbon copy).

Understanding this section is crucial because it clarifies the audience for the message beyond the primary recipient. The inclusion of additional addresses ensures that all relevant parties are kept informed, promoting effective communication within and outside an organization.

The other answer choices focus on different aspects of a communication message. The message security level deals with how sensitive the content is; the content summary summarizes the key points of the message; and the message historical context provides background or rationale for the message itself. None of these pertain specifically to the intended distribution of the message, which is clearly covered by line eight.