问题如下：
Which of the following statements about VAR estimation methods is wrong?
选项：
A.The delta-normal VAR method is more reliable for portfolios that implement portfolio insurance through dynamic hedging than for portfolios that implement portfolio insurance through the purchase of put options.
B.The full-valuation VAR method based on historical data is more reliable for large portfolios that contain significant option-like investments than the delta-normal VAR method.
C.The delta-normal VAR method can understate the true VAR for stock portfolios when the distribution of the return of the stocks has high kurtosis.
D.Full-valuation VAR methods based on historical data take into account nonlinear relationships between risk factors and security prices.
解释：
Full-valuation methods are more precise for portfolios with options, so answers B and D are correct. The delta-normal VAR understates the risk when distributions have fat tails, so answer C is correct. Answer A is indeed wrong. The delta-normal method will be poor for outright positions in options, or their dynamic replication.
选项A说，delta-normal的方法，用保险动态对冲，比有option的对冲方案更好。不觉得有问题啊有option的时候，用delta-normal不好，因为delta会不稳定。。能给再详细解释一下么。谢谢
