What is the function of the throttle in an aircraft?

The throttle in an aircraft serves the primary function of controlling engine power output. When the throttle is advanced, it allows more fuel and air to enter the engine, which increases the power generated by the engine. Conversely, reducing the throttle decreases the fuel and air mixture, thus decreasing the engine's power output. This adjustment directly influences the aircraft's speed, climb rate, and overall performance during flight.

While controlling fuel flow is a part of how the throttle operates, the specific role of the throttle is to modulate the engine's power output, making option B the most accurate answer. Adjusting wing flaps and managing landing gear are unrelated functions that affect flight dynamics and performance but do not involve the throttle.