[单选题]

If a used lube oil analysis indicates excessive chromate content, this means
A．air filtration is inadequate
B．engine coolant is leaking into the lube oil
C．fuel oil is leaking into the lube oil
D．the piston rings are excessive worn

If a used lube oil analysis indicates excessive chromate content, this meansA．air filtration is inadequateB．engine coolant is leaking into the lube oilC．fuel oil is leaking into the lube oilD．the piston rings are excessive worn