Which Sultan added fifth storey to the Qutub Minar?

Firoz Shah Tuglaq

The correct answer is Option 3- Firoz Shah Tuglaq

Started in 1199 by Qutub-ud-din Aibak, the first Sultan of Delhi.
He only managed to complete the basement storey.
Iltutmish, Aibak's successor, added the next three storeys between 1211-1236.
Firoz Shah Tughlaq, who ruled from 1351 to 1388, added the fifth and final storey in 1368. This storey is slightly smaller than the preceding ones.