Correct Answer: (b) Kaushambi
Solution:The present Kaushambi district, carved out of Prayagraj on 4ᵗʰ April 1997, is located 55 km away from the south-west of Prayagraj. Kaushambi has been mentioned several times in Vedic and Jain literature. According to Puranas, Nicakshu, the sixth in line from Parikshita, transferred his capital from Hastinapur to Kaushambi as Hastinapur was revaged by flood, invasion of locusts and upheavals in the Kuru family itself. According to Jain texts. Kushambi was named due to an excess of Kushamb trees in the town. It is the famous pilgrimage site of Jains and Buddhists. Mahatma Buddha preached many times in this city and made number of disciples here. There were many monasteries found here, but the most famous among them was Ghoshitram monastery, which was built by Shresthi Ghoshit.