A command economy would be an economic system that is the opposite of capitalism. A command economy could exist in a socialist system as well, whereby the state controls major businesses in an economy and provides close economic planning for a country's industries rather than allowing private ownership and free markets under capitalism.
The economic theory that is opposite to capitalism is primarily socialism, which advocates for government or community ownership of production means. A command economy, typical of socialist systems, emphasizes government planning and control over economic activities. Thus, the correct answer is C. Socialism.
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