In order to prevent formation of carbon on the injector, the temperature of nozzle tip should be__________________?

In order to prevent formation of carbon on the injector, the temperature of nozzle tip should be__________________?

A. less than 100°C
B. between 100-250°C
C. between 250 – 300°C
D. between 400 – 500°C
E. between 500 – 1000°C