The diameter of fire line/hose must be sufficient to sustain pressure from how many fire pumps?

The correct answer is based on the requirement that the diameter of the fire line or hose must be able to sustain the pressure generated from two fire pumps operating simultaneously. This provision is crucial in firefighting scenarios, as it ensures that adequate water supply is available under high-pressure conditions. Having a fire line that can handle the output of two pumps allows for redundancy and ensures that there is no drop in pressure or flow during critical firefighting operations. The ability to sustain pressure from two fire pumps is a standard safety measure that accounts for potential mechanical failures or the need for increased water supply during larger incidents.

The other choices do not meet this standard. A line designed to only handle one pump may not provide sufficient pressure during large-scale fires, while options for three or four pumps would require a more robust and potentially unnecessary infrastructure, exceeding what is considered typical for fire line design and requirements. This careful balance addresses the operational needs without over-engineering the fire protection systems.