Question Statement:
Which of the following statements regarding the specific speed ($N_s = \frac{N \sqrt{Q}}{H^{3/4}}$) and classification of rotodynamic irrigation pumps are correct?
Options:
- (A) Radial flow centrifugal pumps have relatively low specific speeds, delivering moderate-to-low discharges against high heads
- (B) Axial flow (propeller) pumps have very high specific speeds, designed for large discharges against very low heads (such as drainage lift stations)
- (C) Mixed flow pumps exhibit intermediate specific speeds between radial and axial flow designs
- (D) Specific speed is a dimensionless shape parameter that is independent of physical pump size, depending solely on geometric proportions of the impeller