Metal particles accumulated from the wearing of components in a diesel engine can result from lube oil that has been contaminated with（）.

A.low firing pressure
B.low exhaust temperature
C.mechanical knock in each cylinder
D.fuel knock in each cylinder

A.dry liner
B.wet liner
C.jacket liner
D.corrugated liner

A.Steel brush
B.Fine emery cloth or steel wool
C.A section of the removed compression ring
D.A case hardened scraper