问题如下：
Zhang is a credit analyst in a securities company. For the CDOs and covered bonds, Zhang made the following statements?
Statement 1: Because covered bonds provide dual protection for creditors, they usually carry lower credit risks and offer lower yields.
Statement 2: Compared with investment in corporate bonds, CDOs do not offer unique exposure to a sector or market factor.
Statement 3: Mezzanine and equity tranches of CDOs provide a mechanism for investors to gain additional return if the underlying collateral has strong returns.
According to the information above, which of the following is correct?
选项：
A.Statement 1 and Statement 2 are correct
B.Statement 2 and Statement 3 are correct
C.All the statement are correct
解释：
C is correct.
考点：Structured Financial Instruments概念理解
解析：三个Statements都是正确的，为原版书和讲义给出的结论。
Mezzanine and equity tranches of CDOs provide a mechanism for investors to gain additional return if the underlying collateral has strong returns.
我知道相比第一层，下面两层的收益更好。但是他这里 underlying collateral has strong returns.= underlying 信用质量很好吗？我只知道抵押品质量好，不违约，下面的表现才会比较好，抵押品HAS STRONG RETURNS 未必等于HIGH QUALITY吧？
