In general, the oil mist defectors include a base plate with air blast pumpThe function of air blast pump is to （）crankcase.

A.supply clean air to the measuring compartment of the units for more accuracy

B.generaate the pressure required for the extraction of the oil mist from the

C.generate the pressure required for the extraction of the oil mist from the crankcase

D.supply clean air to the measuring track of the units for more accuracy