Which of the diesel engine cylinder liners listed has internal cooling water passages?（）

A.the water produced during combustion
B.the sulfur in the fuel
C.unburned fuel oil
D.all of the above

A.early injection timing
B.worn orifices in the injection nozzles
C.worn or scored cylinder liners
D.using a fuel with too low of a cetane number

A.during the valve overlap period
B.with only the exhaust valve open
C.at a pressure below atmospheric
D.without cooling the cylinders or pistons