Option b is the correct answer. Deimachus, a Greek from Plataeae, who lived during the third-century BCE, came to India during the reign of Bindusara, the Mauryan ruler. He served as an ambassador to the Mauryan court in Pataliputra. Deimachus was sent by Antiochus I Soter, and he succeeded the renowned ambassador Megasthenes. Both Deimachus and Megasthenes wrote extensively about India, although their works are now lost. They provided various accounts of India's geography and culture, some of which were considered fanciful or exaggerated.