Suppose that the Fed has set the reserve ratio at 10 percent and that banks collectively have $$\$ 2 billion$$ in excess reserves. What is the maximum amount of new checkable-deposit money that can be created by the banking system?
a. $$\$ 0$$
c.$$\$ 2 billion.$$
b. $$\$ 200 million.$$
d. $$\$ 20 billion.$$