Buxar was the capital of

The correct answer is D. Sur.

Buxar was the capital of the Sur dynasty, which ruled over the eastern part of the Indian subcontinent from the 16th to the 17th centuries. The Sur dynasty was founded by Sher Shah Suri, who defeated the Mughal emperor Humayun in the Battle of Chausa in 1539. Sher Shah Suri then went on to conquer most of the Mughal Empire, and he established his capital at Buxar.

The Sur dynasty was a powerful and influential dynasty, and it played a significant role in the history of India. The Sur dynasty was eventually overthrown by the Mughal emperor Akbar in 1556, but its legacy continues to this day.

Option A is incorrect because Ujjaini was the capital of the Malwa Sultanate.

Option B is incorrect because Chero was a kingdom in central India.

Option C is incorrect because Noohani was a town in the Indian state of Bihar.