The correct answer is Guwahati.
Guwahati is the largest city in the Indian state of Assam and the most populous city in the Northeast India. It is also the largest city in the Brahmaputra Valley. Guwahati is located on the south bank of the Brahmaputra River. The city is known for its natural beauty, its historical and cultural heritage, and its vibrant economy.
Dibrugarh is the second most populous city in Assam. It is located in the Dibrugarh district of Assam. Dibrugarh is a major commercial and educational center in the Northeast India. The city is known for its tea gardens, its oil refineries, and its educational institutions.
Silchar is the third most populous city in Assam. It is located in the Cachar district of Assam. Silchar is a major commercial and educational center in the Northeast India. The city is known for its silk industry, its tea gardens, and its educational institutions.
Jorhat is the fourth most populous city in Assam. It is located in the Jorhat district of Assam. Jorhat is a major commercial and educational center in the Northeast India. The city is known for its tea gardens, its oil refineries, and its educational institutions.