According to NFPA 20, a pump must deliver ____________ percent of its rated volume at 65 percent of its pressure rating.

According to NFPA 20, which outlines the requirements for fire pumps, a pump is required to deliver a specific percentage of its rated volume at a predetermined pressure level to ensure its effectiveness during fire suppression activities. The standard mandates that a fire pump must deliver a minimum of 150 percent of its rated volume at 65 percent of its pressure rating. This requirement is crucial because it ensures that the pump has the ability to supply significantly more water than its baseline capacity, enhancing its reliability during emergency situations. By requiring this performance, NFPA 20 aims to provide a margin of safety and ensure that even in less-than-ideal conditions, such as pressure loss or reduced operational efficiency, the fire protection system can still perform adequately.

In contrast, the other choices suggest lower percentages of rated volume, which would not sufficiently meet the demands of a fire protection system, primarily undermining its effectiveness during critical situations when maximum water supply is necessary.