The correct answer is (b), Iltutmish.
Iltutmish was the first Sultan of Delhi to issue regular currency and declare Delhi as the capital of his empire. He was a powerful and successful ruler who expanded the Delhi Sultanate and made it a major power in the Indian subcontinent. He was also a devout Muslim who promoted the spread of Islam in India.
Nasiruddin Mahmud was the second Sultan of Delhi. He was a weak and ineffective ruler who was unable to maintain the power and stability of the Delhi Sultanate. He was eventually overthrown by his own general, Balban.
Aram Shah was the third Sultan of Delhi. He was a short-lived ruler who was killed in battle after only a few months in power.
Balban was the fourth Sultan of Delhi. He was a strong and capable ruler who restored order and stability to the Delhi Sultanate. He was also a ruthless and cruel ruler who is known for his suppression of rebellions and his persecution of Hindus.
Iltutmish was the first Sultan of Delhi to issue regular currency. He also declared Delhi as the capital of his empire. This was a significant event in the history of the Delhi Sultanate, as it marked the beginning of the Delhi Sultanate as a major power in the Indian subcontinent.