Assume That the Required Reserve Ratio for the Commercial Banks

Assume that the required reserve ratio for the commercial banks is 25 percent.If the Federal Reserve Banks buy $3 billion in government securities from the nonbank securities dealers, then, as a result of this transaction, the lending ability of the commercial banking system will increase by

A) $4.5 billion.
B) $9 billion.
C) $12 billion.
D) $15 billion.