Answer:
B, from prices in a market system
Step-by-step explanation:
A market system can be defined as a combination of buyers, sellers and other parties that come together to patronise a product or service.
Buyers and sellers alike can decide what to buy and what not to buy through the prices of goods and services in the market system.
For a seller, if the price of a product is quite costly from the manufacturer, it tells whether the seller would purchase it or not. Likewise, if a buyer approaches a seller for any goods or services, the price of the goods or services determines whether or not the buyer will purchase from the seller.
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