问题如下：
Considering the occurence of default, when compared with secured debt holders, debentures' holders generally have:
选项：
A.higher rank.
B.lower rank.
C.the same rank.
解释：
B is correct.
Debentures represent the unsecured debt. In the event of default, unsecured debt holders' claim rank below those of secured creditors.
这和破产的时候大家都是same level有什么不一样，怎么区分不同的情况
