问一道题：NO.PZ2018062003000162

问题如下：

Which of the following statements is most correct regarding to a limitation of monetary policy during the periods of deflation?

选项：

The central bank cannot control the deflation rate.

Considering the ricardian equivalence.

The central bank cannot let the interest rate fall below zero.

解释：

C is correct.

Once the central bank has cut nominal interest rates to zero to stimulate the economy, it cannot cut them further because the interest rate has a minimum value(0%).

考点：Limitation of Monetary Policy

解析：在 deflation 的状态下，利率只能被央行设置到0的水平，却很难把利率设置到0以下。所以C选项正确，相比较C选项，A选项的解释没有解释根本原因。

李嘉图均衡是财政政策的范畴，不会对 deflation 产生影响，所以B选项不入选。