tb Minar was originally four-storied. Who among the following Delhi Sultans raised the height to the structure by adding the fifth storey?

The Qutb Minar's construction was initiated by Qutb-ud-din Aibak in 1192 CE, who completed only the first storey. His successor, Iltutmish, added three more storeys, bringing the total to four. In 1368, the top storey was damaged by lightning. Firoz Shah Tughlaq repaired the structure and replaced the damaged top storey with two smaller storeys, effectively adding a fifth storey and increasing the tower's height from 72.5 metres to 74 metres [1]. While other Sultans like Alauddin Khalji planned ambitious projects like the Alai Minar, they did not complete them [1]. Firoz Shah Tughlaq is specifically credited with the restoration and the addition of the final fifth storey that defines the structure's current profile.

Sources

1. [1] History , class XI (Tamilnadu state board 2024 ed.) > Chapter 10: Advent of Arabs and Turks > Architecture > p. 152