The river water may contain a lot of pollutants so it can’t be called drinking water. Rain water after falling earth dissolves a lot of soluble matter in it, so it is not fit for drinking in its raw form. Ground water is the term used for the water that flows below the surface of the earth; it may or may not be suitable for drinking. On the other hand, this word potable means clean and safe for drinking. Complete Solution : River water: River water is a surface water source and a part of the water cycle. It can be used for households, irrigation, processing in industries or for the production of energy. A river is a ribbon-like body of water that flows downhill from the force of gravity. A river can be wide and deep, or shallow enough for a person to wade across. Rain water: Water falling as rain that has not collected soluble matter from the soil and is therefore soft is called rain water. Rainwater is naturally designed to water plants, and it can easily be used for your indoor and outdoor gardens. You can use rainwater in watering cans to water plants by hand. You can also attach any rainwater storage tanks directly to an automatic irrigation system. Potable water: Potable water is also known as drinking water, is water that is safe to drink or to use for food preparation. Healthy potable water contains important minerals and it is free of microorganisms, bacteria, chemicals and other contaminants. Ground water: It is the water that occurs below the surface of earth, where it occupies all or part of the void spaces in soils or geologic strata. It is also called subsurface water to distinguish it from surface water, which is found in large bodies like the oceans or lakes or which flows overland in streams. So, the correct answer is “Option C”. Additional Information. Protecting our rivers from getting polluted is very important, for that we should stop the disposal of toxic chemicals into it, also we should use phosphate free detergents and in the village area we shouldn’t use rivers for human excretion activities. Note: Rainwater harvesting system, also called rainwater collection system or rainwater catchment system, technology that collects and stores rainwater for human use. Rainwater harvesting systems range from simple rain barrels to more elaborate structures with pumps, tanks, and purification systems. The non-potable water can be used to irrigate landscaping, flush toilets, wash cars, or launder clothes, and it can even be purified for human consumption.