The best tool to use for removing the carbon ridge at the top of an enginecylinder, prior to removing the piston, is to use（）

A.Faulty turbocharger turbine diffuser ring
B.Faulty turbocharger compressor ring
C.Insufficient cooling water flow
D.Clogged air intake filters

A.Excessive piston blow-by to the manifold
B.Insufficient cooling water flow
C.Accumulated water in the air boxes
D.Clogged air intake filters

A.cause blow-by
B.chemically attack the piston skirt
C.form an emulsion of lube oil and water
D.raise the piston temperature