What color lights are used to mark service roads on an airport?

Answer: C — Red

Service roads on an airport are marked with red lights. This color is used to indicate areas that may be restricted or that require caution due to proximity to airport operations, such as runways and taxiways. The use of red light helps ensure that ground vehicles and personnel are aware of potential hazards and manage their movements accordingly. The distinct color of red serves to alert drivers about the specific nature of their surroundings, promoting safety and compliance with operational procedures. This is particularly important in the fast-paced environment of an airport, where situational awareness is crucial for preventing accidents and ensuring smooth operations.