单选题Excessive oil foaming in the crankcase of a refrigeration compressor is most likely to occur（） when the compressor.Ahas continuously for a long periodBsuction pressure is below normalCoil level is below normalDstarts after a long idle period
单选题
Excessive oil foaming in the crankcase of a refrigeration compressor is most likely to occur（） when the compressor.
A
has continuously for a long period
B
suction pressure is below normal
C
oil level is below normal
D
starts after a long idle period
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