问

问题如下：

Which of the following statments is the result of that money supply cannot affect real things in the short run.

选项：

A.

Price level and employment unaffected.

B.

Monetary policy is invalid.

C.

Money demand will be influenced.

解释：

B is correct.

If money were neutral in the short run, then there would be almost no point to monetary policy.

考点： Money neutrality

解析：如果在短期货币供给不能影响经济中的真实变量，那么货币政策就是无效的，所以B选项说法正确。

货币的供给的变化虽然不一定影响真实变量，但会对物价水平造成影响，所以A选项错误。

货币需求和货币供给是两个不同的概念，所以C选项错误。