Which classification marking appears at the bottom of the first page and provides details about the classification?

The classification marking that appears at the bottom of the first page and provides details about the classification is known as the classification line. This marking includes important information such as the classification level (e.g., Confidential, Secret, or Top Secret), the authority for classification, and the date of declassification.

This marking is essential as it serves to immediately inform the reader of the document's classified status, ensuring that proper handling procedures are followed. The classification line's specific placement at the bottom of the first page allows it to be easily visible while maintaining the document's overall formatting.

In contrast, other markings serve different purposes: footer marking typically refers to standard page numbers or other identifiers rather than specific classification details; portion marking indicates the classification level of individual sections or paragraphs within a document; the banner marking usually appears at the top of the page but doesn’t provide as comprehensive information as the classification line.