单选题A centrifugal pump may fail to deliver water when first started if the （）.Awater seal pipe is pluggedBpump is not primedCseal ring is improperly locatedDimpeller is flooded
单选题
A centrifugal pump may fail to deliver water when first started if the （）.
A
water seal pipe is plugged
B
pump is not primed
C
seal ring is improperly located
D
impeller is flooded
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