The auxiliary (tail) rotor of a helicopter permits the pilot to compensate for and/or accomplish which of the following?

The auxiliary (tail) rotor of a helicopter is crucial for countering the torque generated by the main rotor during flight. When the main rotor turns, it creates torque that tends to rotate the helicopter's fuselage in the opposite direction. The tail rotor generates thrust in the horizontal plane, allowing the pilot to have precise directional control over the helicopter's orientation. This capability is essential for maintaining a straight flight path and for making turns without unwanted yawing motions.

By adjusting the pitch of the tail rotor blades, the pilot can increase or decrease the amount of thrust produced by the tail rotor, effectively compensating for the torque and allowing for controlled yaw movements. This makes it possible to dictate the helicopter's heading and stability during flight. Thus, the tail rotor is integral to ensuring both torque compensation and directional control, confirming that option C is the correct answer.

In contrast, while the main rotor is primarily responsible for lift and descent, the tail rotor does not directly contribute to speed, altitude adjustments, stability in a broader sense, or overall maneuverability in the same way as the other components of the helicopter's flight systems.