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。
选项C这个结论一般应该怎么理解和记忆比较好。
