Which of the listed factors will indicate the most about the ability of a fuel to ignite in a diesel engine?（）

A.Exhaust energy would draw excess air
B.The inertia of the turbocharger rotor causes a time lag which delays the turbocharger speed increase
C.Exhaust gas pumping losses are increased due to turbine windage
D.Exhaust gas back pressure falls slightly due to increased nozzle action

A.use of low viscosity oil in cold weather
B.increased moisture content of inlet air in cold weather
C.increased drag of pistons and bearings due to increased oil viscosity
D.higher compression pressures reached due to smaller clearances existing in the engine during cold weather

A.octane number
B.cetane number
C.viscosity in Saybolt seconds
D.air fuel ratio