The first tin coins were made ______.

A．They were made of copper.
B．They were made of paper.
C．They were square but with a round hole in the center.
D．They were round but with a square hole in the center.

A．different countries use different kinds of money today
B．different things were used as money
C．animals, shells, rice, elephant tusks, monkey tails and salted were used as money
D．cloth, knives, animals , shells, rice, elephant tusks, monkey tails and salted were used as money