Who among the following rulers of Slave dynasty got the title of "Lakh-Baksh"?

Q. Who among the following rulers of Slave dynasty got the title of "Lakh-Baksh"?
Answer: Qutub-ud-din Aibak
Notes: Sultan Qutb-ud-din Aibak also known as "Lakh Baksh Sultan" (or giver of lakhs), who laid the foundation of Sultanate period in India in 1206 AD.