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 is considered to be the greatest ruler of Kamarupa. The kingdom declined in the 9th century CE and was eventually conquered by the Pala dynasty.
The ancient name “Pragjyotishpura” is associated with Kamarupa. Pragjyotishpura was the capital of Kamarupa and was located in the present-day city of Guwahati. The city was founded by the Varman dynasty and was a major center of learning and culture.
The other options are incorrect. Davaka was a kingdom that existed in the 6th century CE. It was located in the present-day state of Manipur. Sonitpura was a kingdom that existed in the 8th century CE. It was located in the present-day state of Assam. Dimasa was a kingdom that existed in the 13th century CE. It was located in the present-day state of Assam.