What are the fundamental principles of the Planned Economy system?

I. Elimination of private property (only public property exists).
II. State intervention in productive and economic matters (absolute State).
III. The State is the only entrepreneur with protection and autarky policies.
IV. Market and prices controlled by the State.
a) I, II and III are correct.
b) II, III and IV are correct.
c) I, III and IV are correct.
d) All statements are correct.