What best describes the disclosure of information that could adversely affect national security?

The option that best describes the disclosure of information that could adversely affect national security is "Sensitive but unclassified." This term refers to information that, while not classified, can still pose risks to national security if disclosed. Such information requires special handling and protection to prevent it from falling into the wrong hands, as its unauthorized release could potentially lead to security threats.

In contrast, "Secret" typically refers to a specific level of classified information that is considered so sensitive that its unauthorized disclosure could cause significant harm to national security. "Confidential" is another classification level that indicates information that could cause harm but at a lesser degree than "Secret." "For official use only" is a designation to limit access but does not necessarily denote a risk to national security on the same level as classified information. "Sensitive but unclassified" clearly captures a category of information that, while not classified, still needs to be actively protected to safeguard national interests.