What are the two types of hydraulic pumps?

• A. Gear Pumps and Vane Pumps
• B. Centrifugal Pumps and Positive-Displacement Pumps
• C. Axial Flow Pumps and Radial Pumps
• D. Power Pumps-Driven by Power Sources; Hand Pumps-Operated Manually

Answer: (D)

The key idea here is how hydraulic pumps are powered or driven. Pumps fall into two broad categories based on their drive: power pumps, which are driven by an external power source such as an engine or electric motor and provide continuous operation, and hand pumps, which are operated manually without an external power source and are used for small flows, testing, or emergency situations. This distinction focuses on the method of actuation rather than internal design or flow type, which is why it’s the best answer. The other classifications describe aspects like internal mechanisms (gear, vane, axial, radial) or general flow behavior (centrifugal vs positive-displacement), not how the pump is powered.