In the operation of a marine propulsion gas turbine, kinetic and thermal energy required to drive the main propeller shaft are extracted by which of the following?

Correct Answer: Option A — Power turbine.

The power turbine is specifically designed to extract the remaining kinetic and thermal energy from the exhaust gases exiting the gas generator. By converting this energy into mechanical torque, the power turbine drives the main propulsion shaft, completing the work extraction phase of the Brayton cycle in marine applications.