问题如下：
Chen, Roll, and Ross (1986) tested the APT model and found several explanatory variables for the average rate of return on stocks traded on the NYSE. Which of the following is not an explanatory variable in their empirical test?
选项：
A. Expected and unexpected inflation
B. The yield spread between high and low risk corporate bonds
C. The yield spread between long and shor maturity
bonds
D. The change in money supply in the economy
解释：
D. The change in money supply in the economy
The explanatory variables were
• The spread between long-term and short-term interest rates (reflecting shifts in time preferences);
• Expected and unexpected inflation;
• Industrial production (reflecting changes in cash flow expectations); and
• The spread between high-risk and low-risk corporate bond yields (reflecting changes in risk preferences).
这个知识点在哪里提到？
