问题如下：
5. Common stock issues in the above market with average systematic risk are most likely to have required rates of return:
选项：
A. between 2 percent and 7 percent.
B. between 7 and 9 percent.
C. 9 percent or greater.
解释：
C is correct.
Based on a long-term government bond yield of 7 percent, a beta of 1, and any of the risk premium estimates that can be calculatedfrom the givens (e.g., a 2 percent historical risk premium estimate or 4.3 percent supply side equity risk premium estimate), the required rate ofreturn would be at least 9 percent. Based on using a short-term rate of 9 percent, C is the correct choice.
老师，这题做是做对了，但还是有个疑问想请教，这里的ERP为什么不能用前一小题算出来的4.3%代入呢？