The correct answer is A) It must have a positive suction. A centrifugal cargo pump is a type of pump that relies on centrifugal force to move the cargo. These pumps require a positive suction, meaning there must be enough pressure at the inlet of the pump to prevent cavitation and ensure proper operation. This is a key requirement for centrifugal pumps. The other options are incorrect: B) It is a positive displacement pump - This is false, as centrifugal pumps are not positive displacement pumps. C) Increasing rotation speed will decrease discharge pressure - This is false, as increasing the rotation speed of a centrifugal pump will actually increase the discharge pressure.