Answer :
Economists describe the US economy as a mixed-market economy because citizens have economic freedoms with some government regulation. The answer to your question is B. I hope that this is the answer that you were looking for and it has helped you.
I believe the answer is: Citizens have economic freedoms with some government regulation
In mixed economy, the resource management in country is handled by both the government and the private sectors.
This allow the citizens to have economic freedoms in choosing the type of goods or service they want to produce, but limited with government regulation in order to help the competition run more fairly.