Option d is the correct answer. Firuz Shah Tughlaq set up a separate department of slaves called Diwan-i-Bandagan. This department was responsible for the administration of slaves in the Delhi Sultanate. The slaves were employed in a variety of tasks, including the military, the bureaucracy, and the royal household. Important Tips Significant facts about Sultanates: The Diwan-i-Ariz was a military department established by Balban in medieval India. It was overseen by the Ariz-i-Mumalik, responsible for recruiting, training, and organizing the army. This institution played a crucial role in maintaining the Sultanate's military strength and administration. Alauddin Khilji introduced a unique branding system for his military horses. Each horse's brand represented its designated capacity and use, facilitating efficient management and organization within the cavalry. This innovation contributed to the effectiveness of his military campaigns and logistical operations. Jalaluddin Khilji was killed by his nephew and son-in-law Alauddin Khilji who succeeded him as the new king of Khilji Dynasty. The real name of Alauddin Khilji was Ali Gurshap. He sat on the throne of Delhi Sultanate in 1296 AD after killing his uncle Jalal ud din Firuz Khilji.