The correct answer is: a) Godavari River.
The Polavaram Project is a multipurpose project under construction on the Godavari River in the Indian state of Andhra Pradesh. The project is designed to provide irrigation to about 1.8 million acres (7.3 million ha), generate 960 MW of hydroelectric power, and provide flood control. The project is expected to cost over Rs. 50,000 crore (US$7.2 billion).
The project has been controversial since its inception. Environmentalists have raised concerns about the project’s impact on the environment, including the displacement of thousands of people and the loss of biodiversity. The project has also been opposed by some political parties, who have argued that it is not economically viable.
Despite the controversy, the project is currently under construction. The first phase of the project is expected to be completed by 2022.
The other options are incorrect because they are not rivers on which the Polavaram Project is being constructed. The Krishna River is located in the Indian states of Andhra Pradesh, Telangana, and Karnataka. The Pennar River is located in the Indian states of Andhra Pradesh and Tamil Nadu. The Tungabhadra River is located in the Indian states of Karnataka and Andhra Pradesh.