题目：
Which one of the following Federal Reserve monetary policies, when pursued in line with the U. S. government’s fiscal policies, would help increase aggregate demand during a period of high unemployment（）
A. An increase in the reserve requirements for financial institutions.
B. A decrease in the discount rate.
C. An increase in the margin requirements at brokerage firms.
答案：
参考答案：B
解析：
A decrease in the Fed’s lending rate is a monetary tool that the Fed can use to increase the money supply, thereby increasing aggregate demand during recessionary times when there is high unemployment. An increase in the reserve requirements, an increase in the margin requirements, and the sale of bonds by the Fed would all be restrictive monetary policies that would reduce the amount of money in the economy and reduce aggregate demand.
