为什么不能选B

NO.PZ201712110100000301 问题如下 The option strategy Singh is most likely to recommento Hopewell is A.collar. B.coverecall. C.protective put. C is correct. A protective put accomplishes Hopewell’s goof short- term priprotection. A protective put provis wnsi protection while retaining the upsi potential. Although Hopewell is concerneabout the wnsi in the short term, he wants to remain investein Walnut shares because he is positive on the stoin the long term. 中文解析虽然Hopewell担心短期内的下跌，但他希望继续投资于核桃的股票，因为他对该股票的长期前景持乐观态度。而Protective put不仅提供了下行保护，同时保留了上行潜力。 老师好，突然有点钻牛角尖。想问下protective put=stock+long put股票下跌时，到了执行价，如果行权岂不是要把手中的stock给对手方，那不就没有持有了？如果不行权，白浪费了期权费？是否long calenr sprea好？

NO.PZ201712110100000301 问题如下 The option strategy Singh is most likely to recommento Hopewell is A.collar. B.coverecall. C.protective put. C is correct. A protective put accomplishes Hopewell’s goof short- term priprotection. A protective put provis wnsi protection while retaining the upsi potential. Although Hopewell is concerneabout the wnsi in the short term, he wants to remain investein Walnut shares because he is positive on the stoin the long term. 中文解析虽然Hopewell担心短期内的下跌，但他希望继续投资于核桃的股票，因为他对该股票的长期前景持乐观态度。而Protective put不仅提供了下行保护，同时保留了上行潜力。 collar=long sto+long put+short call 不仅可以对冲短期下行的风险还可以增加收入，但是题目好像没有提到要降低成本，还有就是长期对股票还是看涨所以不选择collar？