The Tuivai River is a major tributary of the:

Barak River
Manipur River
Chindwin River
Yu River

The correct answer is: Barak River.

The Tuivai River is a major tributary of the Barak River in the Indian state of Manipur. It originates in the hills of the Naga Hills and flows through the Imphal Valley before joining the Barak River near Silchar. The Tuivai River is a major source of irrigation and drinking water for the people of Manipur. It is also a popular destination for fishing and boating.

The Barak River is a major river in northeastern India. It originates in the Manipur Hills and flows through the states of Manipur, Assam, and Tripura. The Barak River is a major tributary of the Brahmaputra River. It is a major source of irrigation and drinking water for the people of northeastern India. It is also a popular destination for fishing and boating.

The Manipur River is a major river in the Indian state of Manipur. It originates in the hills of the Naga Hills and flows through the Imphal Valley before joining the Barak River near Silchar. The Manipur River is a major source of irrigation and drinking water for the people of Manipur. It is also a popular destination for fishing and boating.

The Chindwin River is a major river in Myanmar. It originates in the Kachin Hills and flows through the states of Kachin, Shan, and Sagaing before joining the Irrawaddy River near Mandalay. The Chindwin River is a major source of irrigation and drinking water for the people of Myanmar. It is also a popular destination for fishing and boating.

The Yu River is a major river in China. It originates in the Qinling Mountains and flows through the provinces of Shaanxi, Gansu, and Ningxia before joining the Yellow River near Lanzhou. The Yu River is a major source of irrigation and drinking water for the people of China. It is also a popular destination for fishing and boating.