Credit cards such as Visa and Mastercard are

a. money because they serve as a medium of exchange: it's much like "if it looks like a duck, walks like a duck, and quacks like a duck . . . it's a duck!"
b. money because they are issued by financial institutions, such as banks, and are accepted almost everywhere in place of currency
c. accepted by merchants as if they were money, and therefore they are money
d. as liquid as currency, and therefore they are money
e. convenient but not money because what you are really using when you use a card is your checking account which is the money

E