Steam enters a turbine steadily at 4 MPa and 600°C and exits at 0.2 MPa and 150°C in an environment at 25°C. The decrease in the exergy of the steam as it flows through the turbine is

(a) 879 kJ/kg

(b) 1123 kJ/kg

(c) 1645 kJ/kg

(d) 1910 kJ/kg

(e) 4260 kJ/kg