Iltutmish organized the nobility into a select group of forty called

Iltutmish organized the nobility into a select group of forty called Turkan–e–chahalgani.

Explanation:

The nobility organized into a selective group of people with forty men was done by Shams–ud–din Iltutmish, terming it as the Turkan– e–chahalgani.  The 40 people group selected and formed by Iltutmish were also called by the name of Chalisa.

They were the amirs of Turks, i.e. Turkish nobles or amirs, who were being selected by the 3rd ruler of the Slave dynasty to serve the purpose of eyes and ears for the ruler. They helped him administer the reign efficiently.

the answer is d. amendments.