Suppose Isabelle decides to bake bran muffins. Which result would be a cost?

 - Isabelle will get to eat more muffins. She can make more bran muffins than chocolate muffins.
 - Isabelle will give up the chance to eat chocolate muffins. She thinks chocolate muffins are tastier than bran muffins.
This result is a cost. It involves giving up or spending something that Isabelle wants or needs:
Isabelle will give up the chance to eat chocolate muffins. She thinks chocolate muffins are tastier than bran muffins.