Concept:Real cost is the sacrifice of the next best alternative when a choice is made.Explanation:Real cost is not measured in money.It is measured in terms of the alternative commodities you give up to produce or obtain something.For example, if a farmer uses land to grow maize, the real cost is the other crops he could have grown with the same land.Thus, real cost equals the value of the best alternative forgone.Answer:Option A: Alternative commodities forgone