In a typical gas turbine propulsion plant, the main thrust bearing directly positions which part(s) of the main reduction gear?

Correct Answer: Option A — Low-speed gear

In marine reduction gear arrangements, the main thrust bearing is integrated into the low-speed gear assembly. This bearing is responsible for absorbing the axial propeller thrust and transmitting it to the ship's hull, ensuring the low-speed gear remains properly positioned relative to the pinions and output shaft.