The correct answer is option 4, Qutub-ud-din Aibak. "Lakh Baksh" was a title given to him when he became the ruler. Now let`s analyze the other options.

Option 1, Iltutmish, was a ruler of the Delhi Sultanate and the third Sultan of the Slave Dynasty. Although he was a prominent ruler, he was not known by the title "Lakh Baksh".

Option 2, Balban, was also a ruler of the Delhi Sultanate and the ninth Sultan of the Slave Dynasty. He was known for his strict rule and effective governance, but not by the title "Lakh Baksh".

Option 3, Raziya, was a unique ruler in the Delhi Sultanate as she was the only woman to ascend to the throne. However, she was not known by the title "Lakh Baksh".

In summary, the title "Lakh Baksh", meaning "Giver of Lakhs", was bestowed upon Qutub-ud-din Aibak, making option 4 the correct answer.