During the Gupta period, the coin that was issued in silver was the Rupyaka. The Kakini, Nishka, and Dinar were not issued in silver during this time. The Kakini was a small copper coin used for smaller transactions. The Nishka was a large gold coin used for larger transactions. The Dinar was a gold coin introduced by the Arab invaders and was not issued by the Gupta empire. Therefore, the correct answer is option 3, Rupyaka. It is important to note that the Gupta period was known for its sophisticated coinage system and the use of silver and gold coins played a significant role in trade and commerce during this time.