Answer:
D. the twelve Federal Reserve Banks
Explanation:
The supply of money within an economy is done by the Central Bank of a country
In the United States this central bank is called the Federal Reserve.
The Federal Reserve are in twelve locations: New York, Boston, Philadelphia, Cleveland, Richmond, Atlanta, Chicago, St Louis, Minneapolis,.Kansas City, Dallas, and San Francisco.
The Federal Reserve uses the following tools to regulate money supply in the economy: interest rate, open market operations, and compulsory reserve deposits by banks.