What are the rated capacities of the water pump at different pressures?

The correct answer outlines the performance characteristics of the water pump concerning different pressures. In this case, a water pump's efficiency is measured by its rated capacity at specific pressure levels.

When the water pump operates at 150 psi, it is rated at 100%, which indicates optimal performance and maximum flow output. This level ensures that the pump is fully utilizing its capability to deliver water effectively. However, as the pressure increases to 200 psi, the rated capacity drops to 70%. This reduction is typical as pumps generally face higher resistance at increased pressures, leading to decreased flow rates.

Furthermore, at 250 psi, the capacity decreases further to 50%. This highlights the operational limits of the pump; it cannot maintain high flow rates under excessive pressure conditions. This information is crucial for fire rescue operations, where understanding the pump's capabilities ensures effective management of water resources during firefighting efforts.

The other options do not correctly represent the expected performance characteristics of pumps under pressure, either stating unrealistic capacities at specified pressures or suggesting configurations that would not align with standard pump operation principles. Thus, choice B accurately reflects the typical behavior of water pumps in relation to pressure and is important for ensuring effective firefighting strategies.