What is the minimum intensity required for perimeter lighting measured horizontally 6 inches above ground?

The correct choice is based on the minimum lighting requirements for ensuring safety and security around perimeters. A minimum intensity of 0.2 foot-candle measured horizontally 6 inches above ground is established in various guidelines and standards for outdoor lighting. This level is sufficient to aid in the detection of individuals, vehicles, or potential threats in darkened areas, enhancing the visibility and safety of perimeters.

This measurement is critical because it highlights the importance of adequate lighting in security planning—providing enough illumination helps in deterrence against unauthorized access and enables clearer visual surveillance. When lighting is below this threshold, it may fail to provide the necessary clarity for effective monitoring and security measures.

The other options propose higher levels of lighting that, while beneficial in certain contexts, are not the established minimum requirement for basic perimeter safety.