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.
题目问的是occurance of default ，也就是违约的发生，并没有涉及claim的问题。请问题干中哪一点提示了claim rank 呢？