A.
The U.S. does not necessarily have a free market economy (the country has a mixed market economy), but I digress.
In the U.S., the economy has little to no government interference, whilst North Korea's economy is regulated entriely by the government.
B.
Free Market:
- competition
- private ownership
- limited government
Command:
- low unemployment
- typically offers free universal healthcare
- less inequality
C.
Free Market:
- wide social and economic gap
- lack of optimization
- competition
Command:
- goods production doesn't always match up to the demand
- innovation is discouraged
- rapid mobilization can overshadow societal needs
D.
Both economic systems are bad in my opinion, a mixed economy is more suitable for developed or developing countries.
However, if I had to choose one of the two economies, I would pick a free market economy. I'd choose free market over command economy because the free market economy can still have some government regulation and still adhere to societal needs.