NO.PZ2016010802000215
问题如下：
In practice, both a fixed parity regime and a target zone regime allow the exchange rate to float within a band around the parity level. The most likely rationale for the band is that the band allows the monetary authority to:
选项：
A.
be less active in the currency market.
B.
earn a spread on its currency transactions.
C.
exercise more discretion in monetary policy.
解释：
C is correct.
Fixed exchange rates impose severe limitations on the exercise of independent monetary policy. With a rigidly fixed exchange rate, domestic interest rates, monetary aggregates (e.g., money supply), and credit conditions are dictated by the requirement to buy/sell the currency at the rigid parity. Even a narrow band around the parity level allows the monetary authority to exercise some discretionary control over these conditions. In general, the wider the band, the more independent control the monetary authority can exercise.
考点：Exchange Rate Regimes
解析：
如果本国的货币贬值了，那我该国当局就应该在外汇市场上买本国国币，卖外国货币。这本质上等于政府实施了一个货币政策。那其实就是政府的货币政策被绑架了。如果汇率目标是带有浮动的，比如6.2-6.5这个区间浮动，现在汇率从6.4下跌到6.3，那么此时政府就不用在外汇市场进行干预。那么它的货币政策就比较具有自主性。
老师，我想问一下，关于这道题，如果浮动和固定汇率波动都比较大，那是不是就可以赚一个spread，那为什么B不对呢。
