In a regenerative or recuperative gas turbine cycle configuration, the heat of the turbine exhaust gas is used to do what?

Correct Answer: Option D — Heat the compressor discharge air before it enters the combustor.

Regenerators and recuperators utilize a heat exchanger to capture energy from the turbine exhaust. This heat is transferred to the high-pressure air exiting the compressor before it reaches the combustor. By preheating this air, the system reduces the fuel mass flow required to achieve the desired turbine inlet temperature.