Final answer:
The role of producers in economics is best explained by their function to supply goods and services. They respond to price changes to determine the quantity of supply, following the law of supply to maximize their profits.
Step-by-step explanation:
The statement that best explains the role of producers in economics is 'A. producers supply goods and services.' Producers are crucial to the economic system, as they provide the goods and services that consumers demand. The law of supply dictates a direct relationship between the price of a good or service and the amount a producer is willing to supply. For instance, if the price of gasoline increases, producers are motivated to expand production, thereby increasing the quantity supplied in the market.
Essentially, producers adjust their production levels based on economic signals such as changes in price to maximize profit, which in turn influences their production decisions. Their role is not to purchase goods and services, create market theories, or sell shares for companies, as some of the other options suggest. Instead, their primary objective is the supply side of market transactions, which involves making commodities available to buyers at various price points.