The Loktak Hydroelectric Project is a major source of power in Manipur and is located on the:

Manipur River
Imphal River
Barak River
Yu River

The correct answer is: The Loktak Hydroelectric Project is a major source of power in Manipur and is located on the Barak River.

The Barak River is a major river in northeastern India. It is the largest tributary of the Brahmaputra River. The Barak River originates in the Manipur Hills in Manipur state, India. It flows through the states of Assam and Tripura before joining the Brahmaputra River in Bangladesh. The Barak River is a major source of water for irrigation and drinking water in the region. It is also a major source of hydroelectric power. The Loktak Hydroelectric Project is a major hydroelectric power project on the Barak River. The project was commissioned in 1980 and has a capacity of 1,000 megawatts. The project is a major source of power for the state of Manipur.

The other options are incorrect. The Manipur River is a river in Manipur state, India. It is a tributary of the Barak River. The Imphal River is a river in Manipur state, India. It is the main river in the state and flows through the capital city of Imphal. The Yu River is a river in Manipur state, India. It is a tributary of the Imphal River.