What type of system provides redundancy for flight controls?

The system that provides redundancy for flight controls is fly-by-wire. This technology uses electronic signals to control the aircraft's flight control surfaces instead of traditional mechanical linkages. One of the key advantages of fly-by-wire systems is their inherent redundancy and safety features.

In fly-by-wire systems, multiple sensors, processors, and actuators are utilized to ensure that if one component fails, others can take over, thus maintaining control of the aircraft. This redundancy is vital for enhancing safety and operational reliability, especially in modern aircraft that demand high performance and safety standards.

When comparing to other types of systems, fly-by-light—though it sounds similar—uses optical fibers and is less common in flight control applications. Conventional mechanical systems do not offer the same level of redundancy since they rely on physical linkages and cables which, if damaged, can lead to a complete loss of control unless redundant mechanical systems are designed into the aircraft from the start. The choice of 'none of the above' would not apply since fly-by-wire is indeed a recognized system that meets redundancy requirements in flight controls.