Executive Order 13526 requires that classified information must remain classified for what minimum duration?

Executive Order 13526 states that classified information must remain classified as long as is necessary to protect national security. This reflects the principle that the protection of certain information is critical for the safety and interests of the nation, and classification is not bound by a specific time frame like five or ten years. Instead, the duration of classification is determined by the ongoing relevance of the information in relation to national security needs.

This means that classified status can be reevaluated and potentially lifted when it is deemed that disclosure will no longer harm national security, but until that time, the information must remain protected. The other options suggest specific time limits or indefinite classification without consideration of the necessity for protection, which does not align with the flexible and dynamic nature of the classification system established by the executive order.