Suppose Cameron decides to plant the amaryllises. Which result would be a cost?
A: Cameron will give up the chance to look at the magnolia tree. He thinks it would have looked more beautiful than the amaryllises.
B: He will save some space. The amaryllises will use up less space than the magnolia tree would have used up.
This result is a cost. It involves giving up or spending something that Cameron wants or needs:
Cameron will give up the chance to look at the magnolia tree. He thinks it would have looked more beautiful than the amaryllises.