Cusec, short for cubic feet per second, measures the flow rate of water, corresponding to option [C]. It quantifies the volume of water passing a particular point in a watercourse per unit of time. Cusec is commonly used to assess river flow, irrigation water supply, and water discharge from dams or reservoirs. Understanding flow rates is crucial in hydrology, agriculture, civil engineering, and environmental monitoring. For example, in irrigation, cusec helps determine the volume of water needed to irrigate crops efficiently. In hydroelectric power generation, cusec aids in evaluating the potential energy production of a river. By measuring water flow, cusec provides valuable information for water resource management, flood control, and ecosystem preservation efforts. Accurate measurement and interpretation of cusec data enable informed decision-making and sustainable utilization of water resources in various sectors, contributing to efficient water management and environmental stewardship.