The correct answer is (d). Sher Shah introduced the system of “patta” and “qabuliyat” to help the peasants.
A patta is a document that is issued to a peasant by the government, which gives them the right to cultivate a piece of land. A kabuliyat is a document that is signed by a peasant, which states that they will pay a certain amount of revenue to the government in return for the right to cultivate the land.
Sher Shah introduced this system in order to help the peasants and to increase agricultural production. The patta and kabuliyat system gave peasants a secure right to the land they cultivated, which encouraged them to invest in their land and to improve their agricultural practices. This led to an increase in agricultural production, which benefited both the peasants and the government.
The other options are incorrect. Alauddin Khalji was a medieval ruler who was known for his military conquests. Giyasuddin Tughlaq was a medieval ruler who was known for his administrative reforms. Firuz Shah Tughlaq was a medieval ruler who was known for his religious tolerance.