The most common type of ballast pump on commercial ships is which of the following?

Correct Answer: Option D — Centrifugal

Centrifugal pumps are the industry standard for ballast systems due to their ability to move large volumes of water at relatively low heads. Their simple, robust design, consisting of a rotating impeller within a volute casing, provides the high flow rates necessary for efficient ballasting and deballasting operations on commercial vessels.