The multirotor configuration known as a tricopter uses what method for yaw control?

The correct choice for yaw control in a tricopter is vectored thrust. In a tricopter, which consists of three rotors, each rotor's thrust can be adjusted to create differences in force and direction, allowing for rotation around the vertical axis, which is what yaw control entails. Specifically, the rear rotor on a tricopter is usually capable of tilting or changing its direction of thrust, creating a yaw motion when it directs thrust either to the left or the right. This method of yaw control is effective because it allows for precise maneuverability and stabilization when flying, making it ideal for multirotor applications.

The other methods mentioned do not apply to the functioning of a tricopter for yaw control. Fixed thrust would imply that all rotors operate at the same thrust levels without any adjustment, which does not facilitate yaw movement. Variable pitch involves changing the angle of the rotor blades to manage lift and thrust but does not directly provide yaw control in this specific configuration. Gyroscopic stabilization may help maintain orientation and control, but it does not actively generate yaw movements in the way that vectored thrust does.