Diesel engine lube oil can become contaminated as a result（）

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

A.excessive piston to liner clearance
B.excessive dirt beneath the piston crown that reduces heat transfer
C.faulty nozzle spray
D.all of the above