问题如下：
Which of the following is best described as annualized single monthly mortality?
选项：
A.Contraction risk.
B.Conditional prepayment rate.
C.Public securities association.
解释：
B is correct.
Conditional prepayment rate(CPR) is annualized SMM(single monthly mortality).
Conditional prepayment rate(CPR) is annualized SMM(single monthly mortality).
这个我知道，但是感觉这样的题目怪怪的，实际考试题目不会这么出吧？
