问题如下图：
选项：
A. 
B. 
C. 
D. 
解释：
b选项错在哪里了
NO.PZ2016082404000014问题如下 Mary hIstock anwill sell it two months from now a specifiete in the mile of the month. Mary woullike to hee the priof risk of Istock. How coulshe best hee the Istowithout incurring basis risk? Short a two-month forwarcontraon IBM stock Short a three-month futures contraon IBM stock Short a two-month forwarcontraon the S&P 500 inx Answers A anB are correct. ANSWER: A Basis risk is minimizewhen the maturity of the heing instrument coincis with the horizon of the hee (i.e., two months) anwhen the heing instrument is exposeto the same risk factor (i.e., IBM). 是不是futures就算是两个月也不行？因为自带basis？
NO.PZ2016082404000014 问题如下 Mary hIstock anwill sell it two months from now a specifiete in the mile of the month. Mary woullike to hee the priof risk of Istock. How coulshe best hee the Istowithout incurring basis risk? Short a two-month forwarcontraon IBM stock Short a three-month futures contraon IBM stock Short a two-month forwarcontraon the S&P 500 inx Answers A anB are correct. ANSWER: A Basis risk is minimizewhen the maturity of the heing instrument coincis with the horizon of the hee (i.e., two months) anwhen the heing instrument is exposeto the same risk factor (i.e., IBM). Mary hIstoanwill sell it two months from now a specifiete in the mile of the month. 老师，能翻译下这句话吗？是2个月后卖股票吗？a specifiete in the mile of the month怎么理解？到底什么时候卖股票？in the mile of the month，这个month说的是哪个月？谢谢。
Mary hIstoanwill sell it two months from now a specifiete in the mile of the month. Mary woullike to hee the priof risk of Istock. How coulshe best hee the Istowithout incurring basis risk? Short a two-month forwarcontraon Isto Short a three-month futures contraon Isto Short a two-month forwarcontraon the S&P 500 inx Answers A anB are correct. ANSWER: A Basis risk is minimizewhen the maturity of the heing instrument coincis with the horizon of the hee (i.e., two months) anwhen the heing instrument is exposeto the same risk factor (i.e., IBM). 为什么不能用3个月的期货合约对冲呢？2个月后，我期货合约平仓了呀。
Mary hIstoanwill sell it two months from now a specifiete in the mile of the month. Mary woullike to hee the priof risk of Istock. How coulshe best hee the Istowithout incurring basis risk? Short a two-month forwarcontraon Isto Short a three-month futures contraon Isto Short a two-month forwarcontraon the S&P 500 inx Answers A anB are correct. ANSWER: A Basis risk is minimizewhen the maturity of the heing instrument coincis with the horizon of the hee (i.e., two months) anwhen the heing instrument is exposeto the same risk factor (i.e., IBM). forwcontract不是存在违约风险啊， 万一对手方违约了就一点都hee不掉了，那3个月的future只差了一个月，不是可以再做offsetting什么之类的弥补一下吗？ 就是感觉forwarcontract跟现在持有的future contact都不是一种contract，怎么能完美hee了呢
B如果把3个月改成2个月就可以了吗？futures和forwar都可以的对吗？
