Define "classified information."

Classified information refers to data that requires protection against unauthorized disclosure due to its sensitive nature. This classification is crucial because such information, if exposed, could potentially harm national security or the interests of the United States or its allies. The classification system is designed to restrict access to this type of information to individuals who have been vetted and granted the appropriate security clearance.

The other options do not meet the definition of classified information. Public information, data used for training, and information in government reports can be accessed without special authorization and do not carry the same risks or need for protective measures as classified information does. The distinction is essential in the realm of security and intelligence, where safeguarding sensitive information is a priority.