问题如下：
Which of the following statements about rating is incorrect？
选项：
A. Better(worse) ratings are indeed associated with lower(higher) default rates.
B. The cumulative default rate is often lower for a bond rated B than for a bond rated BBB.
C. There is a striking difference in default patterns between investment-grade and speculative-grade categories.
D. The cumulative default rate is often lower for a bond rated A than for a bond rated BBB.
解释：
B is correct
考点：Credit Rating
解析：
本题是选出说法不正确的选项。高的评级往往意味着低的违约率，投资等级和投机等级类别在违约模式上存在显著差异。A、C说法正确。BBB级别的债券的违约率低于B级别的债券的违约率，B不正确。A级别债券的违约率低于BBB级别的债券违约率。D正确。
老师好，这道题和下面题库里的这道题结论似乎有一点不一样，下面这道题的结论和老师的讲解是对于高评级的债券，累计违约概率更高。如果按照这个思路，本题应该选D吧？