When you must give something up in order to get something else, it is called:

• A. absolute advantage
• B. marginal benefit
• C. market equilibrium
• D. opportunity cost

Answer: (D)

Verified step by step guidance

1. Understand the concept being asked: When you must give something up to get something else, this relates to the idea of trade-offs in economics.
2. Recall the definition of opportunity cost: It is the value of the next best alternative that you give up when making a choice.
3. Compare the given options with the definition: Absolute advantage refers to producing more efficiently, marginal benefit is the additional gain from one more unit, and market equilibrium is where supply equals demand.
4. Identify that the correct term describing giving something up to gain something else is opportunity cost.
5. Summarize that opportunity cost captures the essence of trade-offs and is fundamental in decision-making in microeconomics.