For centrifugal fire pumps, which pairing describes the two stage configurations and shaft orientations?

• A. Single stage; Horizontal
• B. Dual stage; Diagonal
• C. Single and multistage; Horizontal and Vertical
• D. Multistage; Vertical

Answer: (C)

In centrifugal fire pumps, you describe configurations along two dimensions: how many stages (impellers in series) and how the shaft is oriented. A stage configuration can be single-stage (one impeller) or multistage (two or more impellers in series). The shaft orientation can be horizontal or vertical. The pairing that accounts for both dimensions—covering single and multistage as the stage options, and horizontal and vertical as the shaft orientations—is the best fit. This shows that pumps exist in either single-stage or multistage forms and can be mounted horizontally or vertically, depending on design and application. The other options either specify only one stage type or only one orientation, or use nonstandard terms, so they don’t capture both aspects.