What type of metadata reveals that other individuals modified a document?

Embedded metadata is the correct choice because it is specifically designed to include additional information about a document or file that may not be visible in the content itself. This type of metadata can record details such as the author, creation date, modification dates, and the identity of individuals who have made changes to a document.

When a document is edited, embedded metadata can track these modifications, indicating who made the changes and when they occurred, which is crucial in investigations to establish a history of document interactions.

On the other hand, system metadata typically relates to the file's properties as maintained by the operating system and may not include detailed information about who has edited the document. OS metadata similarly focuses on the properties related to the file’s placement and storage rather than changes made by individual users. EXIF headers are specific to image files and contain data about camera settings, date, and other photographic details, but do not address document modifications by individuals.

Overall, embedded metadata is essential for understanding the lineage of a document and who has played a role in its modifications, making it critical for investigative purposes.