What constitutes classified information?

Classified information is specifically defined as data that is deemed sensitive to national security and is restricted from public disclosure. This classification serves to protect a nation's security interests, as the release of such information could compromise military operations, diplomatic relations, or critical intelligence operations. The classification system—commonly denoted by levels such as Confidential, Secret, and Top Secret—helps ensure that only authorized individuals have access to sensitive data based on their need to know and their security clearance.

Other options mentioned do not correctly fit the definition of classified information. Public data with limited access is available to certain groups but does not carry sensitivity regarding national security. Information related to personal data, while it may require protection under privacy laws, does not inherently relate to national security unless it intersects with classified matters. General business information might be sensitive or proprietary, but it lacks the specific governmental and security context that classifies it as national security-related. Thus, B accurately encapsulates the nature of classified information within the framework of personnel security.