The correct answer is: a) Karnataka
The Tungabhadra Project is a joint venture between Andhra Pradesh and Karnataka. It is a multi-purpose project that was constructed on the Tungabhadra River. The project was started in 1956 and completed in 1974. It has a dam, a reservoir, a power plant, and an irrigation system.
The dam is located on the Tungabhadra River, about 100 kilometers from the city of Bellary in Karnataka. The reservoir is formed by the dam and has a capacity of 12,300 million cubic meters. The power plant has an installed capacity of 750 megawatts. The irrigation system irrigates about 2.2 million hectares of land in Andhra Pradesh and Karnataka.
The Tungabhadra Project is a major source of water for irrigation, drinking water, and power generation in Andhra Pradesh and Karnataka. It is also a popular tourist destination.
The other options are incorrect because they are not states that share a border with Andhra Pradesh.