The correct option is D Qutub-ud-din Aibak
Qutub-ud- din Aibak was the founder of the slave dynasty. The early rulers of this dynasty were called the 'Mamluk' Sultans. The word Mamluk is an Arabic word that means 'owned.' Since these Sultans were earlier either slaves of the Turks or were the sons of the slaves, they were called Mamluk Sultans.