Final answer:
The 'invisible hand' concept was developed by Adam Smith, indicating how self-interest in a free market leads to societal benefits without direct government intervention.
Step-by-step explanation:
The concept of the "invisible hand" to describe the guiding function of prices was developed by Adam Smith. Smith introduced this idea in his book The Wealth of Nations, where he described how a free market economy operates effectively through the forces of self-interest, supply, and demand. Smith believed that individuals working for their own gain would, as if guided by an invisible hand, contribute to the overall good of society by providing the goods and services that are most needed. This process would happen without the need for direct governmental intervention in the market, which is the principle of laissez-faire.
Therefore, the correct answer to the student's question is B. Adam Smith.