The correct answer is D. 1228 AD.
The Ahom invasion of Assam took place in 1228 AD. The Ahoms were a Shan people from present-day Myanmar who invaded Assam from the north. They were led by their chief, Sukaphaa. The Ahoms defeated the local rulers and established their own kingdom in Assam. The Ahom kingdom lasted for over 600 years and played an important role in the history of Assam.
Option A is incorrect because the Ahom invasion of Assam did not take place in 1810 AD. The Ahoms were defeated by the British in 1826 AD.
Option B is incorrect because the Ahom invasion of Assam did not take place in 1011 AD. The Ahoms were not founded until 1228 AD.
Option C is incorrect because the Ahom invasion of Assam did not take place in 1538 AD. The Ahoms were not a major power in Assam until the 17th century.