Suppose Finn decides to plant the violets. Which result would be a cost?
Finn will give up the chance to look at the fir tree. He thinks it would have looked more beautiful than the violets. He will save some space. The violets will use up less space than the fir tree would have used up.
Finn is deciding whether to plant violets or a fir tree in his backyard. He wants to make his backyard more beautiful. But he also wants to leave space for doing fun things.
Before you decide to do something, it is often helpful to list costs and benefits.
Costs are what you give up or spend when you decide to do something. Costs involve giving up things that you want or need.
Benefits are what you gain or save when you decide to do something. Benefits involve gaining something that you want or need.
This result is a cost. It involves giving up or spending something that Finn wants or needs:
Finn will give up the chance to look at the fir tree. He thinks it would have looked more beautiful than the violets.