Option d is the correct answer. Pair 1 is correct: Diwan-i-Mustakharaj was Department to realise arrears introduced by Alauddin Khilji. Pair 2 is correct: Diwan-i-Amir-Kohi was Department of agriculture introduced by Muhammad Bin Tughluq. Pair 3 is correct: Firuz Tughluq established a new department called Diwan-i-Khairat or the Department of Charity. It was created to take care of orphans and widows. Pair 4 is incorrect: Diwan-i-Riyasat was Department of Commerce introduced by Alauddin Khilji (not Balban) to implement economic regulations issued by the Sultan and control the markets and prices.