Besides classification level, what other information can appear in portion and banner markings?

The correct choice refers to control markings, which are essential elements in the marking of classified materials. Control markings provide additional context regarding the handling and safeguarding of classified information. These markings can indicate restrictions on distribution, special access requirements, or pertinent handling instructions.

In the realm of classified information, control markings are crucial for ensuring that personnel understand not only the classification level but also any conditions under which the document can be shared, stored, or transmitted. This is particularly important for maintaining security and accountability throughout the lifecycle of classified materials.

While other options like author names, document revisions, and confidentiality notices may also provide useful context, they do not encompass the same operational significance as control markings do in the classification framework. Control markings are specifically designed to align with security protocols and regulations, making them vital for the proper management and protection of classified information.