The correct answer is (d). Ghiyasuddin Tughlaq founded the city of Jaunpur in 1394.
(a) Alauddin Khilji was the Sultan of Delhi from 1296 to 1316. He was a powerful and successful ruler who expanded the Delhi Sultanate. However, he did not found the city of Jaunpur.
(b) Muhammad Tughlaq was the Sultan of Delhi from 1325 to 1351. He was a controversial ruler who was known for his ambitious projects and his erratic behavior. However, he did not found the city of Jaunpur.
(c) Firoz Shah Tughlaq was the Sultan of Delhi from 1351 to 1388. He was a just and benevolent ruler who is credited with many reforms. However, he did not found the city of Jaunpur.
Ghiyasuddin Tughlaq was the founder of the Tughlaq dynasty. He was a powerful and successful ruler who expanded the Delhi Sultanate. He founded the city of Jaunpur in 1394 as a new capital for his empire. Jaunpur became a major center of learning and culture under his rule.