The correct answer is: a) Brahmaputra.
The Brahmaputra is the largest river in Assam, and it has the highest hydropower potential of any river in the state. The Brahmaputra basin is home to a number of large hydropower projects, including the Lower Subansiri Hydroelectric Project and the Dibru-Saikhowa Hydroelectric Project. These projects have the potential to generate a significant amount of electricity, which could help to meet the growing energy needs of Assam and the rest of India.
The Barak is the second largest river in Assam, and it has a significant hydropower potential. However, the Barak basin is home to a number of protected areas, including the Kaziranga National Park and the Manas National Park. These protected areas are home to a number of endangered species, and they have been designated as UNESCO World Heritage Sites. As a result, there are a number of restrictions on the development of hydropower projects in the Barak basin.
The Manas is a tributary of the Brahmaputra, and it has a small hydropower potential. The Manas basin is home to the Manas National Park, which is a UNESCO World Heritage Site. As a result, there are a number of restrictions on the development of hydropower projects in the Manas basin.
The Dhansiri is a tributary of the Brahmaputra, and it has a very small hydropower potential. The Dhansiri basin is home to a number of protected areas, including the Nameri National Park and the Orang National Park. These protected areas are home to a number of endangered species, and they have been designated as UNESCO World Heritage Sites. As a result, there are a number of restrictions on the development of hydropower projects in the Dhansiri basin.