是否可以仍选B？谢谢

问题如下：

Which of the following positions would best mitigate Ahlim’s concern regarding the purchase of his vacation home in six months?

选项：

Sell an at-the-money six-month BRL/USD call option.

Purchase an at-the-money six-month USD/BRL put option.

Take a short position in a six-month BRL/USD futures contract.

解释：

B is correct.

Ahlim could mitigate the risk of the Brazilian real weakening against the US dollar over the next six months by (1) purchasing an at-the money six-month BRL/USD call option (to buy US dollars), (2) purchasing an at-the-money six-month USD/BRL put option (to sell Brazilian reals), or (3) taking a long position in a six-month BRL/USD futures contract (to buy US dollars).

Purchasing an at-the-money six-month USD/BRL put option (to sell Brazilian reals) would mitigate the risk of a weakening Brazilian real. If the Brazilian real should weaken against the US dollar over the next six months, Ahlim could exercise the put option and sell his Brazilian reals at the contract’s strike rate (which would have been the prevailing market exchange rate at the time of purchase, since the option is at the money).

A is incorrect because purchasing (not selling) an at-the-money six-month BRL/USD call option (to buy US dollars) would mitigate the risk of the Brazilian real weakening against the US dollar over the next six months. The long call position would give Ahlim the right to buy US dollars (and sell Brazilian reals). A call on US dollars is similar to a put on Brazilian reals. So, a put to sell Brazilian reals at a given strike rate can be viewed as a call to buy US dollars.

C is incorrect because going long (not short) a six-month BRL/USD futures contract (to buy US dollars) would mitigate the risk of the Brazilian real weakening against the US dollar over the next six months. A long futures position would obligate Ahlim to buy US dollars (and sell Brazilian reals) at the futures contract rate.

中文解析：

背景是继承了一笔BRL的资产，想要6个月后用这笔钱在美国购买一栋住宅。因此担心BRL贬值，对应的就是担心USD升值。

担心BRL贬值，则应该long put on USD/BRL，或者short forward on USD/BRL。

从担心USD升值的角度，则应该long call on BRL/USD，或者long forward on BRL/USD。

注意不论汇率的表达形式是怎样的，记住我们研究的只是位于分母位置的币种。