Option c is the correct answer. Rupaka was the name of the silver coins issued by the Gupta rulers in ancient India. The word Rupaka means "having a form or image" in Sanskrit. The Rupaka coins had various designs and inscriptions on both sides, depicting the images and names of the Gupta kings, their queens, their gods, and their symbols. Some of the most famous Rupaka coins are those of Chandragupta II, Kumaragupta I, and Skandagupta. Important Tips The Rupaka coins were made of silver and weighed about 2 grams. They were modeled after the Roman denarius and the Sassanian drachma, which were also silver coins used by the Roman and Persian empires respectively. The Gupta kings adopted the Rupaka as a symbol of their political and economic ties with the Romans and Persians. The Rupaka coins were widely circulated and accepted as a standard currency in India and other countries. They also reflected the artistic, cultural, and religious achievements of the Gupta period, which is considered as the golden age of Indian history.