The correct answer is C) The centrifugal compressor is frequently used on small, low power turbines. Explanation: Centrifugal compressors are well-suited for small, low-power turbine applications due to their compact design and high efficiency at lower flow rates. The radial flow pattern of the impeller allows centrifugal compressors to operate efficiently at lower power outputs, making them a common choice for small-scale turbine systems. The other options are incorrect: A) the impeller of a centrifugal compressor has a radial inlet and radial discharge, not axial; B) centrifugal compressors can have higher or lower efficiency than axial compressors depending on the application; and D) while centrifugal compressors have a relatively simple design compared to axial compressors, they are not necessarily more complicated or heavier.