What color exhaust will be exhibited when a slow speed two-stroke/cycle main propulsion diesel engine, designed to operate on light and heavy fuel oil, is operated on insufficiently preheated heavy fuel oil?（）

A.low ignition quality
B.a high volatility
C.low ignition delay
D.a high cetane number

A.inoperative turbocharger
B.inadequate fuel supply
C.overload on one cylinder
D.unequal load distribution

A.governor sensitivity
B.exhaust temperature
C.fuel injection pressure
D.speed of the can shaft