Opportunity cost is defined as
a. the highest-valued, next-best alternative that must be given up to obtain something.
b. the variety of uses that a society has for all factors of production.
c. the monetary cost of making a choice under conditions of scarcity.
d. the collection of all alternative goods that could be chosen at any point in time.

The correct answer is A. the highest-valued, next-best alternative that must be given up to obtain something.

Explanation:

The opportunity cost is the cost of the alternative that we waive when we make a certain decision, including the benefits that we could have obtained from having chosen the alternative option.

Therefore, the opportunity cost is those resources that we no longer receive or that represent a cost due to the fact that we have not chosen the best possible alternative, when we have limited resources (usually money and time). The term opportunity cost is also referred to as "the value of the best option not selected."

Cost of opportunity In our life we have to constantly make decisions for any matter, especially if they are related to money. For example, imagine that we have 10 euros and we have several alternatives to spend them (go to the movies, take a walk in the park and save them, dine out ...), the opportunity cost is going to be the benefit that the alternative to that we have given up, fundamentally the one with the highest value.