英文的解析没有看懂，麻烦帮解释一下。

问题如下：

The most appropriate hedging strategy for the 2015 positions, in keeping with Testa’s wishes, is based on a:

选项：

direct hedge on each currency separately.

cross-hedge of the two currencies in the portfolio

minimum-variance hedge of the two currencies in the portfolio.

解释：

A is correct. A direct hedge on each currency is the most appropriate strategy for the long positions in the Australian and New Zealand dollar. The high correlation between the currencies does not help here because the investor will be using forward contracts to sell both of these currencies. The high correlation between the currencies could have been exploited with a cross-hedge or a minimum-variance hedge if one of the foreign assets was held long and the other short.

B is incorrect. The high correlation between the currencies could have been exploited with a cross-hedge or a minimum-variance hedge if one of the foreign assets was held long and the other short.

C is incorrect. The high correlation between the currencies could have been exploited with a cross-hedge or a minimum-variance hedge if one of the foreign assets was held long and the other short. Although a minimum hedge portfolio can be constructed without simultaneous long and short positions, the greatest risk reduction (which Testa desires) would arise if that were to occur.

中文解析：

本题考察的是在投资多种币种时，多种外币资产间的相关性或者说分散化对对冲的影响。

可以看到T同学是有NAD和AUD两种外币资产的，并且告诉我们两种外币资产的相关性是0.85，这说明两种外币资产没有办法做到分散化，所以需要对两个币种分别进行对冲。

Cross hedge：交叉对冲又叫做替代对冲，顾名思义，就是我们本来要对冲A的，比如说我们要用forward合约对冲，但是市场上找不到A的forward合约，考虑到A和B的相关性很高，B可以替代A，于是我们就用B的forward合约来对冲A。

这里的相关性和本题的相关性完全是不一样的哈，本题中是持有外币NZD和AUD，这两种货币都是我们需要对冲的，二者的相关性高说明这两个投资之间没有做到分散化的效果，因此需要我们单独对它们进行对冲。

MVHR其实只是计算需要多少份的forward合约的一种方法。