问题如下：
A decrease in the prices of AAA-rated corporate bonds during a recession would most likely be the result of:
选项：
A.expectations of higher inflation.
B.increases in credit risk premiums.
C.increases in short-term, default-free interest rates.
解释：
B is correct.
During recessions, the risk premium that investors demand on financial assets, particularly those that are not default-free, such as corporate bonds, may rise because investors in general may be less willing and able to take on heightened default risk during such periods. Specifically, the credit risk premium demanded by investors tends to rise in times of economic weakness, when the probability of a corporate default and bankruptcy is highest.
考点：Credit-risky bonds
解析：问的是投资级的公司债在经济衰退的时候为什么价格下降。
A，在经济好的情况下才会预测inflation rate 变大，所以A错。
B，经济差的时候，要求的风险补偿更高，所以折现率变大，债券价格下降，B正确。
C， real short-term interest rates在经济差的时候会下降，所以C错。
按照讲义中的结论，经济差in recession中，政府为了刺激经济，短期R会下降，而the slope of yield curve会steepen, 意味着长期利率会提高，所以对应inflation应该是上升才对，为什么A错呢？
