An economic expansion has caused Treasury yields to increase and absolute credit spreads to narrow. Which of the following is most likely true（）
A. Relative corporate yield spreads to Treasuries will have increased.
B. The yield ratio of BBB-rated bond yields to AAA-rated bond yields may have increased even as their absolute yield spread has decreased.
C. Even if absolute credit spreads had remained the same, the yield ratio and relative yield spread of BBB to AAA bonds could have decreased.
参考答案：C
解析：
Had BBB and AAA yields risen from 5% and 4% , respectively, to 6% and 5% , the absolute yield spread would have remained the same, but the yield ratios would have decreased from 5/4 to 6/5, and the relative yield spread would have decreased from O.25 to 0.20. This is the reason that relative yield spreads are considered a better indicator of yield spread changes.