有一道题，觉得答案有误，请大家帮忙分析一下。题很简单：
An overvalued currency can be considered as:

A. A tax on exports and a subsidy to imports.
B. A tax on imports and a subsidy to exports.

我认为题目问的是产生overvalued currency的原因，可是答案的解释却是effect of overvalued currency。所以我的答案是B，答案给出的是A。请大家说说对这道题的看法。