The correct answer is: A) Raichur Doab.
The Tungabhadra Project is a multi-purpose irrigation and hydroelectric project on the Tungabhadra River in the states of Karnataka and Andhra Pradesh, India. The project was constructed between 1956 and 1974 and is one of the largest irrigation projects in India. The project provides water for irrigation to over 2.5 million hectares of land in the Raichur Doab, a region between the Tungabhadra and Krishna rivers. The project also generates hydroelectric power and provides flood control.
The Raichur Doab is a major agricultural region in India. The region is located in the Deccan Plateau and is characterized by its red soil and dry climate. The region is well-suited for the cultivation of cotton, sugarcane, and rice. The Tungabhadra Project has been instrumental in the development of the Raichur Doab and has helped to improve the lives of millions of people in the region.
The other options are incorrect because they do not refer to major agricultural regions in India. Option B, Malnad, is a region in the Western Ghats of Karnataka. Option C, Coastal Karnataka, is a region along the west coast of Karnataka. Option D, Mysore Plateau, is a region in the southern part of Karnataka.