Which of the following is a defensive security measure?

• A. Patrol scheduling
• B. Red-team testing
• C. Locks and guards
• D. Threat assessments

Answer: (C)

Defensive security measures are controls that directly reduce the chance of intrusion by creating barriers, monitoring for activity, or providing a security presence. Locks and guards fit this idea best because they provide immediate, tangible protection: locks physically prevent entry unless access is authorized, and guards establish a visible presence, deter potential intruders, monitor for suspicious activity, and respond to incidents. Together, they form a practical line of defense that actively protects people and property.

Red-team testing, while valuable, is a simulated attack used to uncover weaknesses in defenses rather than serving as a protective control itself. Threat assessments analyze risks to guide where defenses should be placed, but they don’t by themselves stop intrusions. Patrol scheduling is an administrative or operational measure that helps manage security activity, but it’s not a direct physical barrier or protective device.