Correct Answer: 1540

Solution : The correct answer is 1540 .

In May 1540, Sher Shah Suri, also known as Sher Khan, defeated the Humayun army in the Battle of Kannauj because the gunpowder that the Humayun's army was carrying was left out in the open and grew wet from the heavy rain. Sher Shah Suri was the emperor of India up to 1545, and the Sur dynasty ruled up to 1555, after which Humayun returned to power.