Which of the following best describes the United States?
It has a market economy with no government regulation. This is the only system that can work with a government run by the people,
It has a command economy. A large nation like the United States needs the government to control all growth of business to prevent problems
It has a traditional economy Most communities are focused on providing their own needs with the resources available in the local area
It has a mixed economy The government protects individual rights, such as minimum pay for work and choices in goods and services

The United States is a mixed economy.

You can eliminate the other possibilities with facts;

A market economy is an economy with no government involvement, but that is not the case in America due to business loans, government-located health inspectors and police, etc.

A command economy is an economy with total government involvement. This isn’t the case since a person has freedom to choose or create a business to work at.

A traditional economy is one with things such as tribes and small social groups. (It’s been a while since I’ve learned about this one, so forgive me if my memory’s a bit rusty.) This isn’t the case for obvious reason.

And then, by both process of elimination and the fact that the answer makes sense, we can conclude D is the answer.