Which of the following government policies is most likely to enhance market efficiency according to welfare economics?

In welfare economics, a government policy that is likely to enhance market efficiency is one that corrects market failures, such as taxes on negative externalities or subsidies for positive externalities. For example, if a factory pollutes the air, this pollution can harm others who are not involved in the factory’s production. A government tax on the pollution can encourage the factory to reduce its emissions, leading to better overall air quality and a healthier community. This policy helps align the factory's private costs with the social costs, making the market more efficient by reducing harm to others. Overall, such policies aim to ensure that resources are allocated in a way that maximizes the well-being of society.