问题如下图：
选项：
A. 
B. 
C. 
D. 
解释：
老师好，本题如果用1-（1-0.3%）sqr=0.599%,错在哪里 呢？
NO.PZ2016082406000018 Between 0.30% an0.60% 0.60% Greater th0.60% ANSWER: The marginfault rate increases with maturity. So, this coulbe, for example, 0.50% over the last three years of the six-yeperio This gives a cumulative fault probability greater th0.60%. 你好，请问这里的0.6%怎么来的呢
If the fault probability for A-ratecompany over a three-yeperiois 0.3%, the most likely probability of fault for this company over a six-yeperiois: 0.30% Between 0.30% an0.60% 0.60% Greater th0.60% ANSWER: The marginfault rate increases with maturity. So, this coulbe, for example, 0.50% over the last three years of the six-yeperio This gives a cumulative fault probability greater th0.60%. 请问以下思路来做的话为何不对 三年作为一个考核的周期， 六年内违约等于前三年违约的概率加上前三年不违约、后三年违约的概率，即0.3%+（1-0.3%)*0.3%＜0.6%
怎么看此处的Pmarginal而不是cumulative P
这里的提到，marginfault rate increases with maturity. 但在本章题库的第2题的中说到，marginfault rate is not necessarily increasing over time. 请问，这两个地方的有矛盾吗？具体是如何的？谢谢
