What classification level of information requires safeguarding because its unauthorized disclosure might harm national security?

The classification level that requires safeguarding due to the potential harm to national security from unauthorized disclosure is designated as "Secret." Information classified as Secret is sensitive and, if disclosed, could cause serious damage to national security. This classification is applied to information that requires protection to prevent compromise, particularly in terms of military operations, diplomatic negotiations, and intelligence activities.

The terminology used, specifically "Secret Classification," emphasizes that this level is part of a broader system to ensure proper handling and security of sensitive data. While "Confidential" also relates to safeguarding national security information, it is a lower classification level that indicates a lesser degree of risk if disclosed. Public information, on the other hand, poses no threat to national security if released. Therefore, the specific nomenclature of "Secret Classification" accurately reflects the highest risk of damage among the options provided.