The guidelines requiring employees to report suspicious behavior represent a directive control. Directive controls are policies, regulations, and guidelines that mandate specific actions or behavior to ensure compliance and enhance the security posture of an organization. The focus on behavior and reporting in this scenario aligns with the intention behind directive controls to guide user actions. The other options, while plausible, do not fulfill the purpose of directing specific actions. Technical controls involve technology and devices, deterrent controls aim to discourage but don't direct specific reporting actions, and physical controls involve tangible measures to secure assets, which do not include guidelines for behavior.