Goals have many attributes, which of the following is not a main characteristic or attribute?

Industria specializes in the production of heavy machinery. It exports machinery to the rest of the world and imports oil from the Gulf countries. Based on this information, we can conclude that Industria is a(n) ________ economy

A) closed B) communist C) command D) open

Opportunity cost is defined

a. only in terms of money spent b. as the value of all alternatives not chosen c. as the value of the best alternative not chosen d. as the difference between the benefits from a choice and the benefits from the next best alternative e. as the difference between the benefits from a choice and the costs of that choice