In which year, did Sher Khan defeat Humayun at Kanauj?

1540

The correct answer is Option 3- 1540

Sher Khan defeated Humayun at the Battle of Kanauj in 1540.

This was the second major defeat for Humayun, who had already been defeated by Sher Khan at the Battle of Chausa in 1539. The defeat at Kanauj forced Humayun to flee India and seek refuge in Persia.

Sher Khan's victory at Kanauj was a major turning point in Indian history. It marked the end of the Mughal Empire in India for the next 15 years, and it ushered in a new period of Afghan rule under the Suri dynasty.