Which navigation system utilizes waypoints for route guidance?

The navigation system that utilizes waypoints for route guidance is the flight management system (FMS) that incorporates GPS technology. An FMS is designed to automate a wide variety of in-flight tasks, providing performance and navigation data while optimizing the aircraft's route.

Waypoints are predetermined geographical locations defined by specific coordinates, allowing pilots to follow a clear and organized path during their flight. In an FMS, these waypoints can be set to create a flight plan, enabling the system to guide the aircraft from one waypoint to another efficiently.

While traditional VOR navigation systems do not utilize waypoints in a conventional sense, they rely on radio beacons and are primarily used for tracking the aircraft's position relative to those beacons instead of a defined route with waypoints. Inertial navigation systems (INS) calculate the aircraft's position using internal sensors and do not typically depend on external waypoints for navigation guidance. Similarly, radio direction-finding systems use radio signals to determine direction rather than following a series of waypoints.

The integration of GPS in flight management systems revolutionizes route planning and execution by using waypoints, making A the correct answer.