老师 我不明白为什么AC不提前行权折现要减去D 不提前行权这个红利不是给short方的嘛 long方拿不到啊

请问老师第13题A，D选项怎么不对，该怎么改

请问老师第11题B选项为什么不对，该怎么理解

请问老师第四题题目和选项是啥意思，没看懂

案例的文章在原版书里有吗

原版书原文Settlement risk is the risk due to the exchange of cash flows when a transaction is settled. Failure to perform on settlement can be caused by a counterparty default, liquidity constraints, or operational issues. This risk is greatest when payments occur in different time zones.为什么说这种风险不同时区还款时最大呢？两者有什么联系吗？

原版书上这段：Downgrade risk is the risk that the perceived creditwor-thiness of the borrower or counterparty might deteriorate. In general, deteriorated creditworthiness translates into a downgrade action by the rating agencies, such as Standard and Poor's (S&P), Moody's, or Fitch in the United States, and an increase in the risk premium, or credit spread of the borrower. 这里最后一句的意思不就是说credit spread的增加么？那这个是信用风险啊。为什么习题里面有一个credit spread widen following recent bankruptcies要归属为市场风险呢？

option-adjusted duration是哪里的知识点，能解释一下吗

如何理解这道题解析中的the concave/convex efficient frontier 在CML，没有加入risk-free asset之前efficient frontier不都是convex的吗

老师，在推导asset or nothing call时，杨老师说asset和N(d2)有相关性，这怎么理解？