The correct answer is: a) Kamarupa.
Kamarupa was an ancient kingdom in Assam, India. It was founded in the 3rd century CE by the Varman dynasty. The kingdom reached its peak under the reign of Bhaskaravarman (600-650 CE), who extended its territory to include parts of present-day Bangladesh and Meghalaya. The kingdom declined in the 9th century CE and was eventually conquered by the Pala dynasty of Bengal.
The ancient name “Pragjyotishpura” is associated with Kamarupa. The name means “City of the Eastern Lights”. It was the capital of Kamarupa for over 600 years. The city was located on the banks of the Brahmaputra River. It was a major center of trade and learning.
The other options are incorrect. Davaka was a kingdom in present-day Odisha. Sonitpura was a kingdom in present-day Manipur. Dimasa was a kingdom in present-day Nagaland.