这题A为什么不对？

NO.PZ2018111501000019 问题如下 One of the non-EURcurrenexposures in the Portfolio is GBP. Aron frequently austs his GBPpositions baseon his short-term tacticoutlook. Aron forecasts ththe GBPwill appreciate 5% against the USover the next six months. The currentUSGrate is 1.60 (1 G= 1.60 US. Aron is consiring the six-monthEuropeoption positions with the primary objective of increasing his GBPexposure in line with his forecast, ana seconry objective of minimizing theiniticash outlay. Whiof the tras below will most likely satisfy Aron’sobjectives expiration? A.Tra 1: Buy call with 1.68 strike, sell callwith 1.72 strike. B.Tra 2: Buy call with 1.60 strike, sell callwith 1.68 strike. C.Tra 3: Buy call with 1.60 strike, sell callwith 1.72 strike. B is correct. 考点Strategies toMofy Risk anLower Heing Costs解析预测GBP会增值，所以Buy call with 1.60 strike，未来的增值会使Aron在1.6的现价基础上获益。由于增值幅度为5%， 1.6*（1+5%）=1.68,所以sell call with 1.68 strike可以降低成本。 这里有个问题，如果真判断准确，1.68的时候，就会被行权，那么这部分持仓就short出去了，题目中并没有说要把这部分仓位减掉，只是要尽可能降低成本，按理说用1.72更合适啊，至少这是一个out of 的期权，不会被行权，如果答案是1.68，是否应该加一个条件，就是计划以1.68卖出，这样严谨一些？

NO.PZ2018111501000019 问题如下 One of the non-EURcurrenexposures in the Portfolio is GBP. Aron frequently austs his GBPpositions baseon his short-term tacticoutlook. Aron forecasts ththe GBPwill appreciate 5% against the USover the next six months. The currentUSGrate is 1.60 (1 G= 1.60 US. Aron is consiring the six-monthEuropeoption positions with the primary objective of increasing his GBPexposure in line with his forecast, ana seconry objective of minimizing theiniticash outlay. Whiof the tras below will most likely satisfy Aron’sobjectives expiration? A.Tra 1: Buy call with 1.68 strike, sell callwith 1.72 strike. B.Tra 2: Buy call with 1.60 strike, sell callwith 1.68 strike. C.Tra 3: Buy call with 1.60 strike, sell callwith 1.72 strike. B is correct. 考点Strategies toMofy Risk anLower Heing Costs解析预测GBP会增值，所以Buy call with 1.60 strike，未来的增值会使Aron在1.6的现价基础上获益。由于增值幅度为5%， 1.6*（1+5%）=1.68,所以sell call with 1.68 strike可以降低成本。

NO.PZ2018111501000019 问题如下 One of the non-EURcurrenexposures in the Portfolio is GBP. Aron frequently austs his GBPpositions baseon his short-term tacticoutlook. Aron forecasts ththe GBPwill appreciate 5% against the USover the next six months. The currentUSGrate is 1.60 (1 G= 1.60 US. Aron is consiring the six-monthEuropeoption positions with the primary objective of increasing his GBPexposure in line with his forecast, ana seconry objective of minimizing theiniticash outlay. Whiof the tras below will most likely satisfy Aron’sobjectives expiration? A.Tra 1: Buy call with 1.68 strike, sell callwith 1.72 strike. B.Tra 2: Buy call with 1.60 strike, sell callwith 1.68 strike. C.Tra 3: Buy call with 1.60 strike, sell callwith 1.72 strike. B is correct. 考点Strategies toMofy Risk anLower Heing Costs解析预测GBP会增值，所以Buy call with 1.60 strike，未来的增值会使Aron在1.6的现价基础上获益。由于增值幅度为5%， 1.6*（1+5%）=1.68,所以sell call with 1.68 strike可以降低成本。 1.72 更难实现，不是应该卖这个吗？

NO.PZ2018111501000019 问题如下 One of the non-EURcurrenexposures in the Portfolio is GBP. Aron frequently austs his GBPpositions baseon his short-term tacticoutlook. Aron forecasts ththe GBPwill appreciate 5% against the USover the next six months. The currentUSGrate is 1.60 (1 G= 1.60 US. Aron is consiring the six-monthEuropeoption positions with the primary objective of increasing his GBPexposure in line with his forecast, ana seconry objective of minimizing theiniticash outlay. Whiof the tras below will most likely satisfy Aron’sobjectives expiration? A.Tra 1: Buy call with 1.68 strike, sell callwith 1.72 strike. B.Tra 2: Buy call with 1.60 strike, sell callwith 1.68 strike. C.Tra 3: Buy call with 1.60 strike, sell callwith 1.72 strike. B is correct. 考点Strategies toMofy Risk anLower Heing Costs解析预测GBP会增值，所以Buy call with 1.60 strike，未来的增值会使Aron在1.6的现价基础上获益。由于增值幅度为5%， 1.6*（1+5%）=1.68,所以sell call with 1.68 strike可以降低成本。 我还是不明白为什么这里要short 一个ATM的call, 课上何老师讲为了cover 成本，short a call but it is a OTM call. 谢谢！