The correct answer is A) Lube oil will discharge from the heavy phase discharge port to the sludge tank. If a manually cleaned disk-type centrifugal lube oil purifier contains insufficient sealing water prior to admitting oil flow to the bowl, the lack of sufficient sealing water will prevent the proper formation of the oil/water interface within the purifier bowl. This will result in the lube oil being discharged through the heavy phase (sludge) discharge port instead of the light phase (clean oil) discharge port, causing the lube oil to be directed to the sludge tank rather than being properly purified. The other answer choices are incorrect because: B) the purifier would still subject the lube oil to centrifugal force, C) insufficient sealing water would not directly cause contamination by emulsification, and D) the lube oil would not overheat and flash due to this issue.