Correct option is C
The Iqta system was a significant administrative innovation introduced during the Delhi Sultanate, particularly under the rule of Iltutmish (reigned 1211–1236 CE), the third ruler of the Mamluk (Slave) dynasty.
The Iqta system involved the granting of land (iqta) by the state to military commanders and nobles in lieu of salary.
The revenue collected from the assigned land was used by the Iqta holder (Muqti) to maintain soldiers and administration.
This helped the Sultanate centralize military and administrative power.
Muhammad Ghori: Introduced early Turkish rule, but did not institutionalize the Iqta system.
Balban: Strengthened the nobility and central authority, but came after Iltutmish.
Nasiruddin Mahmud: A relatively weak ruler; Iltutmish’s son, but not known for major administrative reforms.