Combustion gases with a specific heat ratio of 1.3 enter an adiabatic nozzle steadily at 800C and

Question:

Combustion gases with a specific heat ratio of 1.3 enter an adiabatic nozzle steadily at 800°C and 800 kPa with a low velocity, and exit at a pressure of 85 kPa. The lowest possible temperature of combustion gases at the nozzle exit is
(a) 43°C
(b) 237°C
(c) 367°C
(d) 477°C
(e) 640°C