问题如下图：
选项：
A. 
B. 
C. 
解释：
请问一下这题如果投资者下stop buy指令是否正确呢？不是很理解答案的解析，请老师帮忙解释一下，谢谢
NO.PZ2015122802000029问题如下You own shares of a company thare currently trang $30 a share. Your technicanalysis of the shares incates a support level of $27.50. This, if the priof the shares is going wn, it is more likely to stabove this level rather thfall below it. If the pries fall below this level, however, you believe ththe primcontinue to cline. You have no immeate intent to sell the shares but are concerneabout the possibility of a huge loss if the share priclines below the support level. Whiof the following types of orrs coulyou plato most appropriately aress your concern?A.Short sell orr.B.Gootill-cancellestop sell orr.C.Gootill-cancellestop buy orr. is correct.The most appropriate orr is a gootill-cancellestop sell orr. This orr will acteon if the stopriclines below a specifiepri(in this case, $27.50). This orr is sometimes referreto a gootill-cancellestop loss sell orr. You are generally bullish about the stock, incateno immeate intent to sell, anwoulexpea loss on short selling the stock. A stop buy orr is placeto buy a stowhen the stois going up.考点Execution Instructions这道题就是说现在价格是每股30元，技术分析得到该股票的阻力位是27.5元（通常跌倒27.5元就会反弹）。但是如果股票真的跌破阻力位就会出现巨大亏损，投资者目前还不想卖股票，但他也担心出现跌破阻力位的情况，所以应该发布什么指令呢?A就是一个正常的以市场价格卖空的指令，但题干明确说除非大跌投资者并不想现在就卖。B:投资者现在拥有股票，希望在未来股票价格跌破27.5时卖出止损，这就是gootill cancellestop sell orr的作用，stop orr是一个有效性指令，当价格触碰27.5才会执行卖出指令C:stop buy不能解决投资者的顾虑，因为他持有股票担的是股票下跌而不能及时止损，而C是通常是卖空方用来止损的指令。 错题本上的这题我看不明白，short position 为了止损不应该是stop buy吗，为啥选C limit buy，解析看的更糊涂
NO.PZ2015122802000029 问题如下 You own shares of a company thare currently trang $30 a share. Your technicanalysis of the shares incates a support level of $27.50. This, if the priof the shares is going wn, it is more likely to stabove this level rather thfall below it. If the pries fall below this level, however, you believe ththe primcontinue to cline. You have no immeate intent to sell the shares but are concerneabout the possibility of a huge loss if the share priclines below the support level. Whiof the following types of orrs coulyou plato most appropriately aress your concern? A.Short sell orr. B.Gootill-cancellestop sell orr. C.Gootill-cancellestop buy orr. is correct.The most appropriate orr is a gootill-cancellestop sell orr. This orr will acteon if the stopriclines below a specifiepri(in this case, $27.50). This orr is sometimes referreto a gootill-cancellestop loss sell orr. You are generally bullish about the stock, incateno immeate intent to sell, anwoulexpea loss on short selling the stock. A stop buy orr is placeto buy a stowhen the stois going up.考点Execution Instructions这道题就是说现在价格是每股30元，技术分析得到该股票的阻力位是27.5元（通常跌倒27.5元就会反弹）。但是如果股票真的跌破阻力位就会出现巨大亏损，投资者目前还不想卖股票，但他也担心出现跌破阻力位的情况，所以应该发布什么指令呢?A就是一个正常的以市场价格卖空的指令，但题干明确说除非大跌投资者并不想现在就卖。B:投资者现在拥有股票，希望在未来股票价格跌破27.5时卖出止损，这就是gootill cancellestop sell orr的作用，stop orr是一个有效性指令，当价格触碰27.5才会执行卖出指令C:stop buy不能解决投资者的顾虑，因为他持有股票担的是股票下跌而不能及时止损，而C是通常是卖空方用来止损的指令。
NO.PZ2015122802000029问题如下You own shares of a company thare currently trang $30 a share. Your technicanalysis of the shares incates a support level of $27.50. This, if the priof the shares is going wn, it is more likely to stabove this level rather thfall below it. If the pries fall below this level, however, you believe ththe primcontinue to cline. You have no immeate intent to sell the shares but are concerneabout the possibility of a huge loss if the share priclines below the support level. Whiof the following types of orrs coulyou plato most appropriately aress your concern? A.Short sell orr. B.Gootill-cancellestop sell orr. C.Gootill-cancellestop buy orr. is correct.The most appropriate orr is a gootill-cancellestop sell orr. This orr will acteon if the stopriclines below a specifiepri(in this case, $27.50). This orr is sometimes referreto a gootill-cancellestop loss sell orr. You are generally bullish about the stock, incateno immeate intent to sell, anwoulexpea loss on short selling the stock. A stop buy orr is placeto buy a stowhen the stois going up.考点Execution Instructions这道题就是说现在价格是每股30元，技术分析得到该股票的阻力位是27.5元（通常跌倒27.5元就会反弹）。但是如果股票真的跌破阻力位就会出现巨大亏损，投资者目前还不想卖股票，但他也担心出现跌破阻力位的情况，所以应该发布什么指令呢?A就是一个正常的以市场价格卖空的指令，但题干明确说除非大跌投资者并不想现在就卖。B:投资者现在拥有股票，希望在未来股票价格跌破27.5时卖出止损，这就是gootill cancellestop sell orr的作用，stop orr是一个有效性指令，当价格触碰27.5才会执行卖出指令C:stop buy不能解决投资者的顾虑，因为他持有股票担的是股票下跌而不能及时止损，而C是通常是卖空方用来止损的指令。 short sell orr和正常的sell orr有什么区别？
老师A和B有什么区别
A指的是当天有效的指令吗？
