The correct answer is: a) Chutiya Kingdom.
The Chutiya Kingdom was a kingdom that ruled over the Sadiya region in ancient Assam. It was founded in the 13th century by the Chutiya people, who were an ethnic group from the Brahmaputra Valley. The Chutiya Kingdom was a powerful kingdom that lasted for over 200 years. It was eventually overthrown by the Ahom Kingdom in the 16th century.
The Pala Dynasty was a dynasty that ruled over Bengal in the 8th-12th centuries. The Varman Dynasty was a dynasty that ruled over Kamarupa in the 7th-12th centuries. The Kachari Kingdom was a kingdom that ruled over the Cachar region in ancient Assam.
The Chutiya Kingdom was the only kingdom that ruled over the Sadiya region in ancient Assam. The other three kingdoms did not rule over the Sadiya region.