The correct answer is option 2 - 1526 AD. The reign of the Delhi Sultanate came to an end in 1526 AD. The Delhi Sultanate was a Muslim kingdom that ruled over parts of India from the 13th century to the 16th century. It was founded by Qutb-ud-din Aibak in 1206 AD and saw the rule of various dynasties such as the Mamluks (Slave Dynasty), Khilji Dynasty, Tughlaq Dynasty, Sayyid Dynasty, and the Lodi Dynasty. However, in 1526 AD, the Delhi Sultanate was defeated by the Mughal Emperor Babur in the First Battle of Panipat, marking the end of the Delhi Sultanate and the beginning of Mughal rule in India.