How are banner markings formatted?

The correct answer is centered on the standard formatting requirements for banner markings in classified documents. Banner markings must utilize uppercase letters to maintain clarity and ensure that the information is prominently displayed for easy recognition. This standardization is crucial as it aims to prevent any misinterpretation of the classified status of the material being marked. Using uppercase letters also significantly enhances visibility, particularly in environments where quick identification is essential, thereby supporting compliance with security protocols.

The other options do not align with established formatting practices. Using lowercase letters or mixed case could lead to confusion regarding the classification status, as these formats lack the emphasis required for proper classification marking. Additionally, including abbreviations or formatting in languages other than English does not conform to the customary guidelines, which prioritize straightforward communication of the classification level to all personnel across various security levels.