The engine will fail to start unless _____.A.the pressure of the starting air is high enou

The engine will fail to start unless _____.

A.the pressure of the starting air is high enough

B.there is enough air in the air reservoirs

C.the air is supplied into the cylinders in the appropriate sequence

D.all of the above

请帮忙给出正确答案和分析，谢谢！