What is the purpose of turbine stages and how do the HP and LP turbines interact with the compressor?

• A. Turbine stages extract energy to drive the compressor and power the shaft; the HP turbine drives the high-pressure compressor, while the LP turbine drives the low-pressure compressor or produces useful shaft power.
• B. Turbine stages add energy to the air; HP drives the LP compressor; LP drives the HP compressor
• C. Turbine stages cool the exhaust; HP and LP do nothing to the compressor
• D. Turbine stages only stabilize temperatures; HP drives pumps; LP drives fans

Answer: (A)