The best way of conservation of water resources is

Answer: Option D

All the above given points are worthy so as to conserve water. As rain water is the pure water, it can be stored & utilized as per the needs. Hence underground water tanks in Rajasthan, overhead tanks in Tamil Nadu are compulsory. Over utilisation such as over irrigation depletes water resources, hence should be controlled & water be used wisely. Natural water bodies be replenished through reformation.