Quwwat al-Islam mosque and minaret, built during the last decade of the ______ century.

The correct answer is D, twelfth. Qutb-ud-din Aibak began the Quwwat-ul-Islam mosque in 1192, soon after the second battle of Tarain, and the first phase was finished by about 1198, which falls in the last decade of the twelfth century. He laid the foundation of the Qutb Minar beside it in 1199, and Iltutmish completed the minaret. It is counted as the first mosque built in Delhi by the new sultanate, put together with stone taken from earlier temples on the site, which is why its pillars carry older Indian motifs. Iltutmish and later Alauddin Khalji enlarged the courtyard, and the fourth-century iron pillar of Chandra stands within it. Options A, B and C are wrong because the eleventh century is before the sultanate reached Delhi, while the thirteenth and fourteenth centuries cover the later additions rather than the original mosque. Exam tip: Tarain 1192, Quwwat-ul-Islam 1192-98, Qutb Minar begun 1199.