What does the declassification duration reflect when deriving from multiple sources?

The correct answer reflects that the declassification duration derived from multiple sources is determined by the longest duration of any of the sources involved. This approach is taken to ensure that the most restrictive or protective period for classified information is applied, thereby maintaining compliance with security protocols.

When classified information involves several sources with differing declassification timelines, using the longest duration safeguards sensitive elements that may be protected for an extended period. This method is particularly important in ensuring that no information is inadvertently released before it should be, which could compromise national security or violate legal requirements.

Thus, addressing the declassification duration in this manner prioritizes the more cautious approach, effectively protecting all related information contained within the sources.