The correct answer is "unrestricted competition."
A market economy is based on the premise that competition between businesses is a positive element of society. In a market economy, this competition between businesses would help to lower prices for the consumer. For example, if business A charges $100 for a product and business B charges $20, consumers will go to business B in order to purchase the product. Since business A would not get any customers, they would have to lower their prices in order to make them competitive. In a perfect market economy there would be no need for government involvement, as businesses would keep each other in check.