Which signs have red as the predominant color in the upper panel?

The choice that correctly identifies the signs with red as the predominant color in the upper panel is associated with the "Danger" category. In safety signage, red is typically used to indicate a hazard that poses an immediate threat to safety or health, requiring prompt attention and action.

Danger signs are critical in informing individuals of potentially life-threatening situations, and using red as the dominant color helps ensure that these signs are easily recognizable and taken seriously. This use of color not only communicates urgency but also establishes a universal understanding of the severity of the potential hazard.

In contrast, caution signs often use yellow as their primary color to signify slower, less immediate threats, while warning signs may adopt a variety of colors and symbols based on the nature of the hazard but do not primarily rely on red. The term "alert" does not specifically correspond to standardized sign colors and is less commonly associated with any regulatory safety signage framework. Therefore, the identification of danger signs as predominantly red highlights their role in alerting individuals to serious risks effectively.