Explanation:

- Existing Goods: These are goods that are already in existence and owned by the seller at the time of the contract of sale.

- Future Goods: These goods are yet to be manufactured or acquired by the seller after the contract of sale is made.

- Unascertained Goods: These goods are not specifically identified or agreed upon at the time of the sales contract. They are part of a larger quantity.

- Any of the above: All the mentioned forms of goods (existing, future, and unascertained) are categories into which goods can be classified.

Correct Answer: Option: 4 - Any of the above