In the operation of a lube oil clarifier, the position of the oil/water interface should be __________.

Correct Answer: Option A — non-existent

A clarifier is a centrifuge configured to remove solid contaminants from oil without water separation. Because no water is intentionally added or separated, the oil/water interface should be non-existent. If water is present, the unit is not functioning as a clarifier, potentially leading to improper purification and equipment damage.