I believe the answer is:
A. minimal government intervention
In market economy, the government could not decide the type of jobs that the citizens should have and they are free to do whatever they want as their main source of income. It also give companies the freedom to produce the goods that they have a competitive advantage of.
B. property rights
Unlike in communist countries, market economy allow the people to had ownerships of a certain property. The right of ownership cannot be forcefully taken away unless criminal actions were conducted.