When an electricity generating plant features shaft-driven generators, what type of propulsor is generally used for main propulsion?

Correct Answer: Option C — Controllable-pitch propeller

Controllable-pitch propellers allow the engine to maintain constant RPM for shaft-driven generators while varying thrust by changing blade pitch. This configuration is highly efficient for vessels with high auxiliary electrical loads, as it decouples propulsion thrust from the prime mover's rotational speed.