Name the ancient Indian king who wrote the book “Ratnavali”

The correct answer is Option (1) → Harsha Vardhan

Harshavardhana (ruled 606–647 CE), the king of Thanesar and Kannauj, was also a writer. He wrote three Sanskrit plays: Ratnavali, Priyadarshika and Nagananda. His court poet Banabhatta wrote his life story, the Harshacharita.