What does an anti-skid warning light indicate in an aircraft?

An anti-skid warning light indicates that there is an issue with the anti-skid system, either because it has been turned off or there is a malfunction present within the system. The primary function of an anti-skid system is to prevent the wheels from locking up during braking, which helps maintain control and prevents skidding. When the warning light is illuminated, it serves as a crucial alert to the pilot that the safety system aimed at enhancing braking performance is not operational, thus alerting the pilot to take appropriate actions, such as being prepared for possible reduced braking effectiveness or landing on alternate procedures.

In this context, a properly functioning anti-skid system would not illuminate this warning light, as the system is designed to work seamlessly during normal operations. The other options do not provide accurate descriptions of what the anti-skid warning light signifies.