The correct answer is option 2 - Indo-Greeks. The Indo-Greeks were the first kings to issue gold coins in India. They ruled over parts of northwestern India from the 2nd century BCE to the 1st century CE. The Indo-Greeks were a mix of Greek and Indian cultures and their rule during this time led to the interaction and exchange of ideas between these two civilizations. They introduced the concept of issuing gold coins as a form of currency, which was a significant development in the history of Indian monetary systems. These gold coins were typically minted with images of the Greek gods and were used for trade and commerce in the region. This practice of issuing gold coins was later followed by other dynasties in India, but the Indo-Greeks were the pioneers in this regard.