How Does a "Command Economy" Compare to a "Market Economy

How does a "command economy" compare to a "market economy"?

A) Production and distribution decisions are made by central planners in a command economy, but not in a market economy.
B) There is scarcity in command economies, but not in market economies.
C) Command economies are less prone to inflation than are market economies.
D) A command economy is more efficient than a market economy because decision making is centralized.