What is the effect of increased rotor efficiency?

The choice indicating that increased rotor efficiency results in better responsiveness during flight is correct due to the fundamental relationship between rotor dynamics and the overall performance of a rotorcraft. When rotor efficiency is enhanced, it means that the rotor is able to convert the engine's power into lift and thrust more effectively. This improved efficiency contributes to more immediate and precise control movements, allowing the aircraft to respond faster to pilot inputs.

This responsiveness is critical in various flight scenarios, including maneuvering during emergencies, adjusting to changes in flight conditions, and maintaining stability. The enhanced ability to generate lift without a significant increase in power demand allows pilots to execute complex maneuvers with greater ease, resulting in a more agile and responsive aircraft.

In the context of rotorcraft operation, increased efficiency translates to not just operational benefits but also potential safety enhancements due to improved handling characteristics. This is why the correct answer emphasizes the correlation between rotor efficiency and flight responsiveness.