The correct answer is: d) All of the above.
Modernization of canals involves improving the efficiency of the canal system by lining the canals, installing gates and regulators, and desilting the canals. This will help to reduce water losses and improve the distribution of water.
Rehabilitation of tanks involves repairing and restoring tanks to their original condition. This will help to increase the storage capacity of the tanks and improve the efficiency of irrigation.
Investment in watershed development involves developing and managing watersheds to improve water availability and reduce soil erosion. This will help to increase the productivity of agricultural land and improve the livelihoods of farmers.
All of these measures are essential to improve irrigation infrastructure in Tamil Nadu.