选项d怎么理解？

NO.PZ2019070101000029问题如下If a portfolio manager wants to protehis portfolio through portfolio insurance, whiof the following is not the strategy of portfolio insurance?A.Sell 1/lta call option.B.Buy the same amount of put options the unrlying asset.C.Create option synthetically buying anselling the unrlying assets in the proportion of lta of a put.Create option synthetically buying anselling the futures on the unrlying assets in the proportion of lta of a put.A is correct考点lta Hee-Calculation解析Portfolio insuran可以通过直接购买一个市场上的put option来实现，也可以通过标的资产合成有保护的头寸使得所持头寸的lta等于所需期权头寸的lta，或者通过标的期货来合成有保护的头寸同样使得所持头寸的lta等于所需期权头寸的lta。构造合成期权所需的头寸与对冲该期权所需要的头寸刚好相反，这是因为对期权的对冲过程涉及构造一个相同但具有相反头寸的合成期权。A描述的是lta-neutral的做法，即卖出1/lta 的期权份数。老师好，prote某项资产insurance和lta neutral有什么区别吗？A不也是通过购买stock来保护short call吗

NO.PZ2019070101000029问题如下If a portfolio manager wants to protehis portfolio through portfolio insurance, whiof the following is not the strategy of portfolio insurance?A.Sell 1/lta call option.B.Buy the same amount of put options the unrlying asset.C.Create option synthetically buying anselling the unrlying assets in the proportion of lta of a put.Create option synthetically buying anselling the futures on the unrlying assets in the proportion of lta of a put.A is correct考点lta Hee-Calculation解析Portfolio insuran可以通过直接购买一个市场上的put option来实现，也可以通过标的资产合成有保护的头寸使得所持头寸的lta等于所需期权头寸的lta，或者通过标的期货来合成有保护的头寸同样使得所持头寸的lta等于所需期权头寸的lta。构造合成期权所需的头寸与对冲该期权所需要的头寸刚好相反，这是因为对期权的对冲过程涉及构造一个相同但具有相反头寸的合成期权。A描述的是lta-neutral的做法，即卖出1/lta 的期权份数。股票的stolta=1吧

NO.PZ2019070101000029 问题如下 If a portfolio manager wants to protehis portfolio through portfolio insurance, whiof the following is not the strategy of portfolio insurance? A.Sell 1/lta call option. B.Buy the same amount of put options the unrlying asset. C.Create option synthetically buying anselling the unrlying assets in the proportion of lta of a put. Create option synthetically buying anselling the futures on the unrlying assets in the proportion of lta of a put. A is correct考点lta Hee-Calculation解析Portfolio insuran可以通过直接购买一个市场上的put option来实现，也可以通过标的资产合成有保护的头寸使得所持头寸的lta等于所需期权头寸的lta，或者通过标的期货来合成有保护的头寸同样使得所持头寸的lta等于所需期权头寸的lta。构造合成期权所需的头寸与对冲该期权所需要的头寸刚好相反，这是因为对期权的对冲过程涉及构造一个相同但具有相反头寸的合成期权。A描述的是lta-neutral的做法，即卖出1/lta 的期权份数。 A描述的是lta-neutral的做法，即卖出1/lta 的期权份数。老师，这句话不明白。

NO.PZ2019070101000029 问题如下 If a portfolio manager wants to protehis portfolio through portfolio insurance, whiof the following is not the strategy of portfolio insurance? A.Sell 1/lta call option. B.Buy the same amount of put options the unrlying asset. C.Create option synthetically buying anselling the unrlying assets in the proportion of lta of a put. Create option synthetically buying anselling the futures on the unrlying assets in the proportion of lta of a put. A is correct考点lta Hee-Calculation解析Portfolio insuran可以通过直接购买一个市场上的put option来实现，也可以通过标的资产合成有保护的头寸使得所持头寸的lta等于所需期权头寸的lta，或者通过标的期货来合成有保护的头寸同样使得所持头寸的lta等于所需期权头寸的lta。构造合成期权所需的头寸与对冲该期权所需要的头寸刚好相反，这是因为对期权的对冲过程涉及构造一个相同但具有相反头寸的合成期权。A描述的是lta-neutral的做法，即卖出1/lta 的期权份数。 put和call本来就都可以，主要是1/lta对么