What markings do the top and bottom of a classified email need?

The correct marking for the top and bottom of a classified email is banner markings. Banner markings serve a critical purpose in the classification of information as they clearly indicate the overall classification level of the document at a glance, ensuring that anyone who accesses the email is immediately aware of its sensitive nature.

These markings typically include the classification level, such as "Confidential," "Secret," or "Top Secret," and they are crucial for maintaining security protocols. This helps prevent unauthorized disclosure and ensures that individuals handling the email understand the need for caution regarding its contents. Banner markings provide a consistent and recognizable format that aids in the identification and proper handling of classified communications across different platforms and organizations.

The other options mentioned, while related to classified information handling, do not specifically denote the top and bottom markings required for classified emails. For instance, subject line markings and footer markings are used for other classifications and notices but are not the main identifiers for a classified email. Control markings refer to specific supervisory or procedural instructions that assist in managing classified materials but do not fulfill the same function as banner markings.