An ideal-gas mixture of helium and argon gases with identical mass fractions enters a turbine at 1500 K and 1 MPa at a rate of 0.12 kg/s, and expands isentropically to 100 kPa. The power output of the turbine is
(a) 253 kW
(b) 310 kW
(c) 341 kW
(d) 463 kW
(e) 550 kW