The Sultan who was also known as ‘Lakh Baksh’ is: 

Correct option is C

Qutbuddin Aibak, the founder of the Delhi Sultanate, was famously known as 'Lakh Baksh', which means "giver of lakhs" (a reference to his generosity).
He earned this title because of his generosity in distributing wealth and gifts to his subjects, especially during his reign as the Sultan of Delhi.
Additional Information:
Qutbuddin Aibak was originally a slave of Muhammad Ghori, the ruler of the Ghurid dynasty, and later rose to power as a military commander. After the death of Muhammad Ghori, Aibak declared himself the Sultan of Delhi in 1206.
He is also known for his contributions to architecture, most notably starting the construction of the Qutb Minar in Delhi, which is a UNESCO World Heritage Site.
Other Options:
Muhammad bin Tughlaq : He was a Sultan of the Delhi Sultanate known for his ambitious but often failed policies. He was not known by the title 'Lakh Baksh'.
Iltutmish : Hewas a prominent ruler of the Delhi Sultanate and the father of Raziya Sultana. He is known for consolidating and strengthening the Delhi Sultanate but was not referred to as 'Lakh Baksh'.
Ghiyasuddin Tughlaq : He was the founder of the Tughlaq dynasty. He is not known by the title 'Lakh Baksh'.