Which of the following economic principles is most closely associated with the concept of opportunity cost?

Opportunity cost is an important economic principle that helps us understand the value of what we give up when we make a choice. When we decide to use our time or resources for one thing, we are also deciding not to use them for something else that could be valuable. For example, if you choose to spend your Saturday working on a school project instead of going to a friend's birthday party, the opportunity cost is the fun and memories you miss out on at the party. This principle teaches us to think carefully about our choices and consider what we might be sacrificing. Understanding opportunity cost can help us make better decisions in both our personal and financial lives.