问题如下图：
选项：
A. 
B. 
C. 
解释：put option 不应该是negative吗？
NO.PZ2016031201000034 问题如下 A Europecall option ana Europeput option are written on the same unrlying, anboth options have the same expiration te anexercise price. expiration, it is possible thboth options will have: A.negative values. B.the same value. C.positive values. B is correct.If the unrlying ha value equto the exercise priexpiration, both options will have zero value sinthey both have the same exercise price. For example, if the exercise priis $25 anexpiration the unrlying priis $25, both the call option anthe put option will have a value of zero. The value of option cannot fall below zero. The holr of option is not obligateto exercise the option; therefore, the options eahave a minimum value of zero. If the call ha positive value, the put, finition, must have a zero value anviversBoth cannot have a positive value. 中文解析Put和call同时有负value。这个首先可以排除，因为option value肯定是大于等于0的。value一样put call同时有正value我们知道 put= max[0, X-ST] call=max[0,ST-X] ，X-ST与ST-X是相反的，不可能同时大于0或者小于0。它们只可能相等，且相等的时候，就是value=0的时候，即ST=X 到期日的时候option的value=0这个是一般结论吗？
NO.PZ2016031201000034 问题如下 A Europecall option ana Europeput option are written on the same unrlying, anboth options have the same expiration te anexercise price. expiration, it is possible thboth options will have: A.negative values. B.the same value. C.positive values. B is correct.If the unrlying ha value equto the exercise priexpiration, both options will have zero value sinthey both have the same exercise price. For example, if the exercise priis $25 anexpiration the unrlying priis $25, both the call option anthe put option will have a value of zero. The value of option cannot fall below zero. The holr of option is not obligateto exercise the option; therefore, the options eahave a minimum value of zero. If the call ha positive value, the put, finition, must have a zero value anviversBoth cannot have a positive value. 中文解析Put和call同时有负value。这个首先可以排除，因为option value肯定是大于等于0的。value一样put call同时有正value我们知道 put= max[0, X-ST] call=max[0,ST-X] ，X-ST与ST-X是相反的，不可能同时大于0或者小于0。它们只可能相等，且相等的时候，就是value=0的时候，即ST=X RT
NO.PZ2016031201000034 call option的value为啥是max（0，s-x）不应该是max（0，s-x/(1+rf)^T）吗
由于老师上课反复提到op=IV+TV，所以expiration时TV=0，但是op=IV一定不可能是negative的________________________________________________但看到熊竹老师在之前回答提到option price和option value是等效的，这一点不太理解为什么呢？call pri= max（0，S-X）put pri= max（0，X-S）上面两个都是price啊，并不是value，为什么直接等价来推value相同呢
老师，这个问题应该给一个前提条件吧，即“在到期日的spot pri= forwarprice”，才满足option value=0吧？
