Option b is the correct answer. The correct chronological order is Qutub Minar, Tughlaqabad Fort, Lodhi Garden and Fatehpur Sikri. Qutub Minar in red and buff standstone is the highest tower in India. Qutbu'd-Din Aibak laid the foundation of Minar in AD 1199. Tughlaqabad Fort is a ruined fort in Delhi, which was built by Ghiyasud- din Tughlaq, the founder of Tughlaq dynasty, of the Delhi Sultanate in 1321. Lodhi Garden was set up in between the 15th and 16th centuries by the Sayyid and Lodhi rulers. The city of Fatehpur Sikri was founded in 1569 by the Mughal Emperor Akbar, and served as the capital of the Mughal Empire from 1571 to 1585. It is a UNESCO World Heritage Site.