Which of the following Greek Explorers is considered to have left the earliest account of India?

Q. Which of the following Greek Explorers is considered to have left the earliest account of India?
Answer: Scylax
Notes: The earliest Greek Account of India was left by Scylax of Caryanda who was sent by Kind Darius-I of Persia to follow the course of river Indus and find out where it led. His original works are now lost.