Which economic system emphasizes the need for a nation's government to regulate economic activity?

The economic system that emphasizes the need for a nation's government to regulate economic activity is Mercantilism. This system, which was prevalent from the 16th to the 18th century, is characterized by the belief that a nation's strength is directly related to its wealth, primarily measured in gold and silver. To achieve this wealth, governments implemented various regulations on trade and commerce, often through protective tariffs and monopolistic practices, to ensure that exports surpassed imports.

Mercantilism aimed to create a favorable balance of trade and was characterized by strong governmental intervention in the economy. This intervention included controlling trade routes, establishing colonies for resources, and ensuring that wealth remained within the nation. The focus was on boosting national power and securing resources, which required active regulation by the state.

In contrast, capitalism generally emphasizes private ownership and free markets with minimal government interference. Socialism advocates for government ownership of the means of production but does not focus on the same nationalistic goals as Mercantilism. Feudalism is a system based on land ownership and obligations, more concerned with social hierarchies than economic regulation. Therefore, Mercantilism is the most suitable answer in the context of government regulation in economic activities.