Which instrument system provides backup flight information?

The standby flight instruments are designed specifically to provide essential flight information in the event of a primary instrument failure. These instruments typically include an altimeter, airspeed indicator, and artificial horizon, which are critical for pilots to maintain situational awareness and control of the aircraft under adverse conditions.

Having this backup system ensures that the pilot has access to vital information regarding the aircraft's altitude, speed, and orientation, which are crucial for safe flying, especially during critical phases of flight or when there is a malfunction of the main electronic displays.

While other systems listed may serve important roles in the aircraft’s operation, they do not fulfill the specific function of providing a direct backup for the primary flight instruments, making the standby flight instruments the correct choice for this question.