The correct answer is: d) All of the above.
Major irrigation projects in Arunachal Pradesh focus on micro-irrigation systems, diversion of river water, and construction of dams and reservoirs.
Micro-irrigation systems are small-scale irrigation systems that are designed to deliver water to individual crops or small areas of land. They are often used in areas where there is limited water availability or where the terrain is difficult to irrigate with traditional methods.
Diversion of river water is the process of taking water from a river and using it for irrigation or other purposes. This can be done by building dams or canals to divert the water, or by pumping the water out of the river.
Construction of dams and reservoirs is another way to store water for irrigation. Dams are built across rivers to create reservoirs, which can then be used to store water for irrigation during the dry season.
All of these methods are used in Arunachal Pradesh to irrigate crops and provide water for drinking and other purposes.