The founder of the medieval Odantapuri Monastery (now Bihar Sharif) was:

Bakhtiyar Khalji
Qutubuddin Aibak
Ghiyasuddin Balban
Iltutmish

The correct answer is: Bakhtiyar Khalji.

Bakhtiyar Khalji was a Turkic general who invaded the Indian subcontinent in the 12th century. He is credited with the founding of the medieval Odantapuri Monastery (now Bihar Sharif).

Qutubuddin Aibak was a Turkic slave who served as the first Sultan of Delhi. He was not the founder of the Odantapuri Monastery.

Ghiyasuddin Balban was a Turkic general who served as the third Sultan of Delhi. He was not the founder of the Odantapuri Monastery.

Iltutmish was a Turkic general who served as the fourth Sultan of Delhi. He was not the founder of the Odantapuri Monastery.

The Odantapuri Monastery was a Buddhist monastery that was founded in the 5th century CE. It was one of the most important Buddhist monasteries in India. The monastery was destroyed by Bakhtiyar Khalji in the 12th century.

Bakhtiyar Khalji was a ruthless conqueror who was known for his brutality. He is said to have killed thousands of people during his conquest of India. He is also said to have destroyed many temples and monasteries.

The Odantapuri Monastery was one of the many victims of Bakhtiyar Khalji’s conquest. The monastery was destroyed and its monks were killed. The destruction of the Odantapuri Monastery was a major blow to Buddhism in India.