NO.PZ2020033003000093
问题如下：
In the process of structuring a securitization, credit enhancements are often applied. Which of the following statements is least accurate about credit enhancements?
选项：
A.The liability side of the SPV has a lower cost than the asset side of the SPV to create an excess spread prior to administration costs.
B.
Credit enhancements play an important role in the securitization process for both the asset- backed security (ABS) and mortgage-backed security (MBS) issues.
C.
To reduce the risk of the asset-backed security (ABS), over collateralized is often used in the most senior class of notes.
D.ABS issues may use a margin step-up that increases the coupon structure after a call date
解释：
C is correct.
考点：Credit enhancements
解析：
tranche的最底层才更需要overcollateralized来给信用进行增级，而不是C选项里的the most senior class
选项A可以解释一下么，谢谢
