Suppose Alec decides to join the Theater Club. Which result would be a cost?
A: Alec will save some time. He would have spent more time in the Photography Club than in the Theater Club.
B: Alec will give up the chance to be in the Photography Club. He would have had more fun in the Photography Club than in the Theater Club.
This result is a cost. It involves giving up or spending something that Alec wants or needs:
Alec will give up the chance to be in the Photography Club. He would have had more fun in the Photography Club than in the Theater Club.