What should be prominently posted to ensure physical security?

Prominently posting the perimeter of the area requiring physical security is essential as it clearly defines the boundaries of secured areas and communicates to individuals the limits of authorized access. By marking the perimeter, it establishes a physical barrier that helps deter unauthorized entry and enhances security by making it evident where protection measures are in place. This visibility acts as a first line of defense and provides a clear indication to personnel and visitors alike regarding which areas are restricted.

In contrast, while the design of the facility, emergency contact numbers, and access control policies are important components of a comprehensive security plan, they do not serve the primary purpose of delineating secure areas. The design of the facility might inform people about its layout but does not specifically address boundary security. Emergency contact numbers, although critical in case of an emergency, do not contribute to immediate physical security measures. Access control policies outline procedures but, without visible markers of the perimeter, individuals may not know where those policies apply. Thus, posting the perimeter stands out as a crucial measure for ensuring physical security.