The correct answer is (a) Iltutmish.
The iqta system was a system of land grants in medieval India. It was introduced by Iltutmish, the second Sultan of the Delhi Sultanate, in the 13th century. Under the iqta system, land was granted to nobles in return for their military service. The nobles were responsible for collecting taxes from the peasants and using the revenue to maintain their troops.
The iqta system was a successful way of raising revenue and maintaining a strong military. However, it also led to the rise of powerful nobles who could challenge the authority of the sultan. The iqta system was eventually abolished by the Mughal emperor Akbar in the 16th century.
Option (b), Balban, was a Sultan of the Delhi Sultanate who ruled from 1266 to 1287. He was a strong and capable ruler who restored order to the sultanate after a period of instability. However, he did not introduce the iqta system.
Option (c), Alauddin Khalji, was a Sultan of the Delhi Sultanate who ruled from 1296 to 1316. He was a powerful and ruthless ruler who expanded the sultanate’s territory. However, he did not introduce the iqta system.
Option (d), None of the above, is incorrect. The iqta system was introduced by Iltutmish.