问一道问题

问题如下：

The interpretation of the intercept is the mean of the annual growth rate of the money supply:

选项：

A. over the enter entire period

B. after the shift in policy

C. before the shift in policy

解释：

C is correct. In a simple regression with a single indicator variable, the intercept is the mean of the dependent variable when the indicator variable takes on a value of zero, which is before the shift in policy in this case.