ANS:D - 5 to 10

The design period in years for pumping plants typically ranges from 5 to 10 years. Pumping plants are essential components of water supply and wastewater systems, used to lift water from lower to higher elevations or to overcome hydraulic resistance in pipelines. The design period for pumping plants refers to the anticipated lifespan or duration for which the plant's design is intended to be effective and efficient. Given the significant investment and infrastructure involved in pumping plants, they are designed to operate reliably over an extended period. Therefore, a design period of 5 to 10 years is commonly adopted to ensure that the pumping plant can meet operational requirements and performance expectations over its service life.