Consider an ideal gas refrigeration cycle using helium as the working fluid. Helium enters the compressor at 100 kPa and -10°C and compressed to 250 kPa. Helium is then cooled to 20°C before it enters the turbine. For a mass flow rate of 0.2 kg/s, the net power input required is
(a) 9.3 kW
(b) 27.6 kW
(c) 48.8 kW
(d) 93.5 kW
(e) 119 kW