Marie decides to work all summer rather than going on vacation. she will be able to earn money and learn new skills but will not be able to spend much time with her friends. what is the opportunity cost in this scenario? going on vacationspending time with friendsearning moneyworking all summer

At every point in our social behavior (and not only that), we are faced with choices. While each choice may have its merits, we choose the best for us. But even the one we deem best is associated with at least one negative element; we lose the opportunity to pursue another choice. Thus, by choosing not to go on vacation, she loses the opportunity to spend some time with her friends. Think of another scenario; you have a test tomorrow and decide not to go to a party. While this is a good decision in the long-term, you pay the opportunity cost of not going to the party (not going on vacation respectively) and thus the opportunity cost is again "spending time with friends".

Yes thats true but what is the question