Answer: B) Command
For instance, the government sets prices of all goods in a command economy and they also set the production level (ie how much of a certain item to produce).
A traditional economy is based on the culture and often uses the barter method. A market economy uses currency instead of bartering, and the prices are determined by market forces (ie the people in the market). A mixed economy is a combination of command and market.
An example of a mixed economy is the United States where free market forces determine prices though there are government regulations set up to ensure the economy doesn't go south, and to ensure fair trade practices are followed.