No one should enter Zone _______ until they are screened.

The correct answer indicates the highest level of risk associated with a specific environment, often emphasizing the need for safety protocols and screening procedures before entry. Zone Three typically represents a controlled area that may have elevated safety concerns, possibly due to potential exposure to hazardous materials or the need for specialized equipment.

Screening in this context serves to ensure that individuals entering the area are fit for duty and not carrying items that could compromise safety or negatively impact the environment. This aligns with the standards and protocols often set in regulated environments, such as medical imaging or other specialized facilities, which prioritize safety and compliance with established safety regulations.

The other zones may represent areas with different levels of risk or requirements for entry that do not necessitate screening in the same manner as Zone Three, which places a strong focus on personal safety and the protection of the surrounding environment or equipment. Thus, emphasizing screening before entry into Zone Three is critical for maintaining operational safety.