问题如下：
Which of the following exchange rate regimes that requres monetary authority to hold same scale of foreign exchange reserves to back its domestic currency issuance :
选项：
A. target zone regime
B. a currency board.
C. dollarization.
解释：
B is correct.
If the country with a currency board want to issue its domestic currency, it must hold foreign currency as a 100% reserve.
考点：Exchange Rate Regimes
解析：国家想发行本国货币，它必须持有100%的外汇储备。这是一种典型的 currency board 制度.
香港也是盯住美元的，相当于美元化，C为什么不对呢？