Suppose both Ross and Vivian produce butter and cheese. When Ross works for 10 hours a day, he produces 6 pounds of butter and 24 pounds of cheese. When Vivian works for the same hours, she produces 20 pounds of cheese and 40 pounds of butter. Ross's opportunity cost of producing a pound of butter is:
- 4 pounds of cheese.
- 18 pounds of cheese.
- 1/4 pounds of cheese.
- 5 pounds of cheese.