The correct answer is B: Jalal-ud-din. The Khilji dynasty was founded by Jalal-ud-din Firuz Khilji. He ascended to the throne of Delhi in 1290 AD, marking the end of the Mamluk (Slave) dynasty and the beginning of the Khilji rule. Jalal-ud-din was initially a military commander under the Mamluks and seized power through a coup, establishing a new line of rulers in the Delhi Sultanate.
A: Alauddin refers to Alauddin Khilji, who was the nephew and son-in-law of Jalal-ud-din Firuz Khilji. Alauddin was a highly successful and powerful ruler, known for his military conquests, administrative reforms, and market regulations. He greatly expanded the Khilji empire but was not its founder; he succeeded Jalal-ud-din after assassinating him.
C: Qutb-ud-din refers to Qutb-ud-din Aibak, who was the founder of the Mamluk dynasty (also known as the Slave dynasty). He was a former slave general of Muhammad of Ghor and established the Delhi Sultanate in 1206 AD. His dynasty preceded the Khilji dynasty, making him the founder of a different ruling line.
D: Mubarak Shah refers to Qutb al-Din Mubarak Shah Khilji, who was one of the later rulers of the Khilji dynasty. He was the son of Alauddin Khilji and ruled for a brief period after his father's death. He was not the founder but a successor within the dynasty.
Therefore, Jalal-ud-din Firuz Khilji holds the distinction of being the founder of the Khilji dynasty, initiating a new era in the history of the Delhi Sultanate.