Correct the Cost Statements. Consider the following statements about cost. For each incorrect statement, provide a correct statement about the relevant cost.

a. One year ago, I loaned a friend $100, and she just paid me back the whole $100. The loan didn't cost me anything.

b. An oil refinery bought a million barrels of oil a month ago, when the price was only $75 per barrel, compared to $120 today. The cost of using a barrel of oil to produce gasoline is $75.

e. Our new football stadium was built on land donated to the university by a wealthy alum. The cost of the stadium equals the $50 million construction cost.

d. If a commuter rides a bus to work and the bus fare is $2, the cost of commuting by bus is $2.