The correct answer is A. Sibsagar.
The Ahom kingdom was a kingdom in the Brahmaputra valley of northeastern India, which existed from the 13th century to the 19th century. The capital of the Ahom kingdom was shifted several times during its existence, but the most important capital was Sibsagar. Sibsagar was founded in the 17th century by the Ahom king Pratap Singha, and it remained the capital of the kingdom until the 19th century. Sibsagar was a major center of trade and culture during the Ahom period, and it is home to many important historical monuments, including the Rang Ghar (a royal palace), the Kareng Ghar (a military barracks), and the Talatal Ghar (a watchtower).
B. Guwahati is a city in the Indian state of Assam. It is the largest city in the state and the second largest city in the Northeast India. Guwahati is the gateway to the Northeast India and is a major center of trade and commerce. The city is also home to many important educational institutions, including the Indian Institute of Technology Guwahati, the Assam University, and the Gauhati Medical College.
C. Jorhat is a city in the Indian state of Assam. It is the headquarters of Jorhat district and the third largest city in the state. Jorhat is a major center of trade and commerce and is also home to many important educational institutions, including the Jorhat Engineering College and the Jorhat Medical College.
D. None of these is the correct answer.