What color are mandatory instruction signs for airfield driving?

Answer: C — Red with white text

Mandatory instruction signs for airfield driving are designated by a red background with white text. This color scheme is intentionally used to ensure high visibility and to convey critical information to pilots and drivers in the airfield environment. The color red is universally recognized as a signal for "stop" or to draw attention, which is vital for ensuring safety and compliance with instructions on the airfield. These signs indicate that a specific action must be taken, such as "STOP," "HOLD," or "GIVE WAY." In contrast, other colors have different meanings; for example, green typically denotes information that is not mandatory, yellow is often used for caution, and blue is generally reserved for informational signs. Understanding these color codes is essential for anyone involved in airfield operations to ensure a safe and efficient environment.