Unregulated markets
In unregulated markets, there are no restrictions on the transactions that can take place. This means that buyers and sellers are free to engage in any type of transaction they desire, without any governmental or regulatory oversight. Unregulated markets are characterized by a lack of rules, regulations, and restrictions imposed by a governing body.

Regulated markets
On the other hand, regulated markets are subject to various rules and regulations imposed by a governing body, such as a government agency or a regulatory authority. These regulations are put in place to ensure fair and orderly trading, protect investors, and maintain the stability of the market. In regulated markets, there are restrictions on certain types of transactions, and participants must comply with the established rules and regulations.

Spot market
The spot market is a type of market where financial instruments, such as commodities or currencies, are traded for immediate delivery. Transactions in the spot market are settled "on the spot," meaning the buyer pays for and takes immediate possession of the asset. In the spot market, transactions are typically carried out between buyers and sellers directly or through brokers. While there may be regulations governing the spot market, it is generally considered to be less regulated compared to other types of markets.

Future market
The futures market, also known as the futures exchange, is a type of market where participants can buy or sell contracts for the future delivery of a specific asset, such as commodities or financial instruments. In the futures market, transactions are standardized contracts that specify the quantity, quality, and delivery date of the underlying asset. The futures market is regulated by regulatory authorities to ensure fair trading practices and protect market participants.

Explanation
Out of the given options, unregulated markets (option A) are the only ones where there are no restrictions on transactions. Unregulated markets allow participants to engage in transactions freely without being bound by specific rules or regulations. This means that buyers and sellers have more flexibility in terms of the types of transactions they can enter into. However, it is important to note that unregulated markets may also carry certain risks, as there is no regulatory oversight to ensure fair trading practices or protect investors. Participants in unregulated markets should exercise caution and conduct thorough due diligence before engaging in any transactions.