The correct answer to the question is:
B. Opportunity cost
Explanation:
1. **Opportunity Cost**: This term refers to the value of the next best alternative that is given up when a decision is made. In this scenario, when Kate considers the alternatives she would be giving up by spending her savings on buying a car, she is evaluating the opportunity cost associated with that decision.
Therefore, Kate's thought process of weighing the alternatives that will be lost if she chooses to spend her savings on buying a car falls under the economic concept of opportunity cost.
