Liaison officers must comply with certification procedures outlined in which Army Regulation?

The correct answer is rooted in the fact that Army Regulation 380-10 specifically addresses the requirements and guidelines for the protection of information within the Department of the Army. This regulation covers various aspects of information security, including the roles and responsibilities of personnel who handle sensitive or classified information.

In the context of liaison officers, the regulation outlines the key certification procedures they must adhere to, ensuring that these personnel are properly vetted and trained to manage the exchange of information securely and according to Army standards. This is crucial for maintaining operational security and safeguarding national defense interests.

The other options, while they pertain to other important areas concerning Army operations, do not specifically focus on the certification processes related to liaison officers. For example, AR 190-13 deals with physical security, AR 600-20 is about Army command policy including equal opportunity, and AR 15-6 pertains to the administrative investigation process. Therefore, these regulations do not encompass the specific certification requirements that are relevant to liaison officers as outlined in AR 380-10.