The correct answer is C) displace an equal amount of water from the bowl seal. When water is removed from lube oil passing through a centrifugal purifier, the water removed will displace an equal amount of water from the bowl seal. This is because the centrifugal force within the purifier bowl separates the water from the oil, and the water displaced from the oil needs to go somewhere, which is the bowl seal. The other options are incorrect because: A) the water removed would not be retained in the bowl, as it needs to be discharged; B) the diameter of the oil column would not narrow due to water removal; and D) the water displaced from the heavy phase discharge port would be equal to the amount removed from the oil, not less.