The correct answer is: Tank irrigation.
Tank irrigation is a traditional method of irrigation that is widely used in Tamil Nadu. It involves the construction of tanks or reservoirs to store rainwater, which is then used to irrigate crops. Tank irrigation is a sustainable and efficient method of irrigation, and it is well-suited to the climate and topography of Tamil Nadu.
Canal irrigation is another method of irrigation that is used in Tamil Nadu. It involves the construction of canals to transport water from rivers or reservoirs to fields. Canal irrigation is a more efficient method of irrigation than tank irrigation, but it is also more expensive to construct and maintain.
Drip irrigation is a modern method of irrigation that is becoming increasingly popular in Tamil Nadu. It involves the use of drippers to deliver water directly to the roots of plants. Drip irrigation is a very efficient method of irrigation, and it can save water and fertilizer.
Sprinkler irrigation is another modern method of irrigation that is used in Tamil Nadu. It involves the use of sprinklers to spray water over crops. Sprinkler irrigation is a more efficient method of irrigation than flood irrigation, but it can also be more expensive to operate.
In conclusion, tank irrigation is the most widely used method of irrigation in Tamil Nadu. It is a traditional and sustainable method of irrigation that is well-suited to the climate and topography of the state. Canal irrigation is another method of irrigation that is used in Tamil Nadu, but it is more expensive to construct and maintain than tank irrigation. Drip irrigation and sprinkler irrigation are modern methods of irrigation that are becoming increasingly popular in Tamil Nadu, but they are also more expensive to operate than tank irrigation.