The correct answer is (a) Tajuddin Yeldoz.
Tajuddin Yeldoz was the ruler of the Khwarezmian Empire from 1220 to 1221. He was the son of Muhammad II, the last Khwarezmian ruler. After the Mongol invasion of Khwarezmia, Tajuddin Yeldoz fled to India, where he was killed in battle by Iltutmish in 1221.
Nasiruddin Kubacha was a claimant to the throne of the Delhi Sultanate. He was the son of Iltutmish’s brother Ruknuddin Firuz. Nasiruddin Kubacha rebelled against Iltutmish in 1229, but was defeated and killed.
Ali Mardan was a general in the Delhi Sultanate. He was a loyal supporter of Iltutmish and helped him to consolidate his power. Ali Mardan was killed in battle in 1232.
Malik Altunia was a Rajput ruler of the Mewat region. He was a rival of Iltutmish and fought against him on several occasions. Malik Altunia was finally defeated and killed by Iltutmish in 1236.