Explanation:

Option (c) is correct. The King Harshavardhana was mention in by all the three authors Harishena, Banabhatta and Xuan Zang in their prashastis, a Sanskrit word for 'in praise of', and books of their respective kings for which they worked. Banabhatta was the court poet of the King Harshavardhana. Banabhatta wrote the biography of the king, the Harshacharita, in Sanskrit. The biography gives us the genealogy of Harsha and ends with his becoming king. Ravikriti was the court poet of the king Pulakeshin II, the best known Chalukya ruler. According to Ravikriti Pulakehsin II led expedition along both the west and the east coast. He mentioned that Pulakeshin II also had checked the advance of the the King Harsha. There is an interesting play of the words in the poem. The poet says that after his defeat Harsha was no longer Harsha. Xuan Zang was one of the best-Known chinese Buddhist pilgrims who came to India around 1400 years ago. He came to visit places associated with the life of Buddha. He also spent a lot of time in Harsha's court and left the detailed account of what he saw.