Macroeconomics 20th Edition by Campbell McConnell ,Stanley Brue ,Sean Flynn

Exercise 42

Suppose that you are given a $100 budget at work that can be spent only on two items: staplers and pens. If staplers cost $10 each and pens cost $2.50 each, then the opportunity cost of purchasing one stapler is:
a. 10 pens.
b. 5 pens.
c. zero pens.
d. 4 pens.