Correct option is D
Information Booster:
Made Delhi his capital - Iltutmish shifted the capital of the Delhi Sultanate from Lahore to Delhi, firmly establishing Delhi as the political center.
Received Khil‛at (robes of honour) from the Caliph - Iltutmish received an investiture (Khil‛at) from the Abbasid Caliph Al-Mustansir Billah in 1229 CE, which legitimized his rule.
Issued Tanka and Jital currency - He introduced a bimetallic currency system – Tanka (silver coin) and Jital (copper coin), establishing monetary stability.
Established the Department of Diwan-i-Arz - This department, which dealt with military administration, was established by Alauddin Khalji, not Iltutmish.
Additional Knowledge:
Diwan-i-Arz :-
A military department responsible for the recruitment, training, and inspection of the army.
Created by Alauddin Khalji to maintain a strong and efficient military system.