NATO classified documents, except for NATO RESTRICTED, must be stored in accordance with which directive?

The correct choice is based on guidance related to the handling and storage of NATO classified documents. Specifically, the pertinent directive outlining the procedures for the storage and handling of NATO classified documents—excluding those classified as NATO RESTRICTED—is DoD Directive 5100.55.

This directive provides the framework for the management of NATO classified information and ensures that all personnel and facilities adhere to the necessary security measures to protect sensitive information shared among NATO member nations. Within NATO operations, establishing stringent protocols for classified materials, aside from the lower classification of NATO RESTRICTED, is crucial for maintaining national security and international relations.

While other directives mentioned in the choices focus on different aspects of security and information assurance, they do not specifically address the storage requirements for NATO classified documents. Therefore, understanding the specific context of DoD Directive 5100.55 is essential for compliance and for fulfilling the responsibilities of a Foreign Disclosure Officer to handle and protect classified NATO information appropriately.