10. Where such unauthorized disclosure could reasonably result in damage to the
national security, the information may be classified as "Confidential" and must be properly
safeguarded. Where such unauthorized disclosure could reasonably result in serious damage to
the national security, the information may be classified as "Secret" and must be properly
safeguarded. Where such unauthorized disclosure could reasonably result in exceptionally grave
damage to the national security, the information may be classified as "Top Secret" and  must be properly safeguarded.

[Useful definitions of the classifications.]