Answer:
A.
Step-by-step explanation:
The free-market-based economy allows more freedom in decision-making for private companies. This an capitalism characteristic. That doesn't mean that government don't participate, actually they do. Government participation in this case refers to ensure that markets are open, working and with no monopolies, that's all. But, government don't get involved into decision making in private companies.
On the contrary, when government participate on decision making, that's called Socialism. In this type of economy, government commands the national economy, create a central plan and make sure that private companies follow it.
Therefore, U.S economy is considered as a mixed economy because government commands economy only in defense of people, guaranteeing retirement benefits, medical care and other benefits.