5. Which of the following is the best example of using money as a store of value?

a. A customer pays in advance for $10 worth of gasoline at a gas station.

b. A babysitter puts her earnings in a dresser drawer while she saves to buy a bicycle.

c. Travelers buy meals on board an airline flight.

d. Foreign visitors to the United States convert their currency to dollars at the airport.

e. You use $1 bills to purchase soda from a vending machine.