The correct answer is: a) Medieval period.
The Chutiya Kingdom was a powerful state that had influence over parts of eastern Arunachal Pradesh during the Medieval period. It was founded in the 12th century by the Chutiya dynasty, and it reached its peak in the 16th century. The Chutiya Kingdom was eventually conquered by the Ahom Kingdom in the 17th century.
The Pre-historic era is the period of time before written history. It is a long and complex period, and it is not well-understood. There is evidence that humans have been living in Arunachal Pradesh for at least 50,000 years. However, there is no evidence that there was a powerful state in Arunachal Pradesh during the Pre-historic era.
The Mughal Empire was an empire that ruled over much of India from the 16th to the 18th centuries. It was founded by Babur, a descendant of Timur and Genghis Khan. The Mughal Empire did not have any influence over Arunachal Pradesh.
British colonial rule was the period of time when India was ruled by the British. It began in the 17th century, and it ended in the 20th century. The British did not have any influence over Arunachal Pradesh until the 19th century.