The correct answer is: D. Jorhat
The Ahom dynasty was a Tai-Ahom kingdom that ruled over the Brahmaputra Valley in northeastern India from the 13th to the 19th centuries. The dynasty was founded by Sukaphaa, who migrated from present-day Yunnan in China to Assam in 1228. The Ahoms established their capital at Charaideo in 1253.
In 1536, the Ahom capital was moved to Garhgaon. Garhgaon remained the capital of the Ahom kingdom until 1696, when it was moved to Sibsagar. Sibsagar remained the capital of the Ahom kingdom until 1826, when it was captured by the British.
After the capture of Sibsagar, the Ahom capital was moved to Jorhat. Jorhat remained the capital of the Ahom kingdom until 1853, when the Ahom dynasty was overthrown by the British.
Nazira, Sivasagar, and Charaideo were all important cities in the Ahom kingdom, but they were never the capital.