Carbon dioxide enters a converging–diverging nozzle at 60 m/s, 310°C, and 300 kPa, and it leaves the nozzle at a supersonic velocity. The velocity of carbon dioxide at the throat of the nozzle is
(a) 125 m/s
(b) 225 m/s
(c) 312 m/s
(d) 353 m/s
(e) 377 m/s