Final answer:
Protecting private property enhances efficiency in a free market by providing security for investments, whereas establishing a minimum wage might not enhance market operation as it can lead to unemployment and distort labor market signals.
Step-by-step explanation:
Among the government actions that would most enhance efficiency in a free market, according to most economists, is protecting private property. This action provides a foundational element for market activities because it ensures that individuals can securely own and invest in assets, which in turn, solidifies the incentives to engage in economic activities. Conversely, of the options listed, establishing a minimum wage is the action that might not enhance the operation of a free market, as it can create a price floor above the equilibrium wage, potentially leading to a surplus of labor (unemployment), and distortion of market signals for labor.