An early goldsmith banker earned a profit (sometimes a large profit) simply by writing notes to certify that a person had deposited a certain amount of gold in his vault. By writing more notes than the amount of gold held, the goldsmith could lend the notes and charge interest on them. What were the main benefits from the activities of the goldsmith bankers?
a) An increase in the use of barter
b) The elimination of the money multiplier
c) Creating a means of payment
d) The establishment of a central bank