The correct answer is (b), Alauddin Khalji.
Ghari or House-tax was a tax levied on the houses of the people in the Delhi Sultanate. It was first introduced by Alauddin Khalji in the 13th century. The tax was used to finance Alauddin’s military campaigns and to improve the infrastructure of the Delhi Sultanate.
Balban was a 13th-century ruler of the Delhi Sultanate. He was a strong and capable ruler who restored order and stability to the sultanate after a period of chaos. However, he did not introduce Ghari or House-tax.
Mohammad bin Tughlaq was a 14th-century ruler of the Delhi Sultanate. He was a brilliant but erratic ruler who was responsible for some of the most ambitious and innovative policies of the Delhi Sultanate. However, he also made some disastrous decisions, such as the transfer of the capital from Delhi to Daulatabad. He did not introduce Ghari or House-tax.
Firoz Shah Tughlaq was a 14th-century ruler of the Delhi Sultanate. He was a just and benevolent ruler who is credited with many reforms, such as the construction of canals and roads. However, he did not introduce Ghari or House-tax.