Opportunity cost is an economic term that simply says that when you make a purchase, you forego another alternative. Money, or the lack of it is usually the main reason for making the decision to make a decision to get one product and forego another one.
Therefore, it is the term that describes the process of making an economic decision by considering both the advantages and problems that may arise from the decision.
The correct answer among the choices listed is option A. A group of interdependent people who have organized in such way as to share a common culture and feeling of unity is a society. These group of people live together in a particular area having common interests and traditions.