Which of the following King introduced Iqta system?

The correct answer is Option 2- Iltutmish

Shamsa ud-din Iltutmish of the Delhi Sultanate is credited with introducing the Iqta system in India.

The Iqta system was a land-based administrative and revenue-generating system implemented in the Delhi Sultanate.
According to the Iqta system the Sultanate divided its territories into various tracts of land called Iqtas.
These Iqtas were not permanent land grants but rather assignments given to individuals.
Individuals entrusted with managing an Iqta were known as Muqtis or Walis.
Muqtis were authorized to keep a portion of the agricultural produce collected from the land.
The remaining portion was sent to the state treasury.