The United States began as more of an option A: market economy but grew more mixed as the government added laws and regulations. In a market economy, the production of goods and prices are determined by the competition in the market.
Market economy
The above answer is explained in further detail as given below:
The market economy is one of the economic systems in which market decisions are created by the forces of demand and supply.
The United States also started as a market economy, and it then became a more mixed form of government with the addition of new laws and regulations.
Therefore, the correct answer is option A.