The correct answer is (a) Punch-marked coins.
Punch-marked coins were the earliest coins used in the Indian subcontinent. They were made of silver or copper and were stamped with a variety of symbols, including animals, geometric shapes, and religious symbols. The coins were used as a form of currency and were also used in religious ceremonies.
Copper coins were also used in the Indian subcontinent, but they were not as common as punch-marked coins. Copper coins were made of pure copper and were not stamped with any symbols. They were used as a form of currency, but they were not as valuable as punch-marked coins.
Alloy coins were made of a mixture of metals, such as silver and copper. They were not as common as punch-marked coins or copper coins. Alloy coins were used as a form of currency, but they were not as valuable as punch-marked coins or copper coins.
Gold coins were the most valuable type of coin used in the Indian subcontinent. They were made of pure gold and were stamped with a variety of symbols, including animals, geometric shapes, and religious symbols. Gold coins were used as a form of currency, but they were also used as a form of wealth and were often stored in temples or other safe places.