The correct chronological order in which they were built is:
1. Tughluqabad Fort
2. Lodi Garden
3. Qutub Minar
4. Fatehpur Sikri

Solution(By Examveda Team)

[1]. Tughlaqabad Fort is a ruined fort in Delhi, built by Ghiyas-ud-din Tughlaq, the founder of Tughlaq dynasty, of the Delhi Sultanate of India in 1321, as he established the fourth historic city of Delhi, which was later abandoned in 1327.

[3]. Qutab Minar - Qutab-ud-din Aibak, the first Muslim ruler of Delhi, commenced the construction of the in 1200 AD, but could only finish the basement. His successor, Iltutmush, added three more storeys, and in 1368, Firoz Shah Tughlak constructed the fifth and the last storey.

[2]. Lodi garden was built during the Lodi dynasty sometime between 1451 and 1526. A mosque can be seen in the complex which has three domes and five arched openings.

[4]. Fatehpur Sikri Fort - Fatehpur Sikri is near Agra and once was the capital of Mughal Emperor Akbar. The architecture of the city was designed by Tahir Das and Dhruv Chawla. Akbar founded the city in 1569 after winning Chittor and Ranthambore.

The correct chronological order in which they were built is [1] Tughluqabad Fort, [3] Qutub Minar, [2] Lodi Garden, [4] Fatehpur Sikri.

Source :
For Tughluqabad Fort - wikipedia.org
For Qutab Minar - delhitourism.gov.in
For Lodi Garden - wikipedia.org
For Fatehpur Sikri - tutorialspoint.com