NO.PZ2016031201000044
问题如下：
A European put option on a dividend-paying stock is most likely to increase if there is an increase in:
选项：
A.carrying costs.
B.the risk-free rate.
C.dividend payments.
解释：
C is correct.
Payments, such as dividends, reduce the value of the underlying which increases the value of a European put option. Carrying costs reduce the value of a European put option. An increase in the risk-free interest rate may decrease the value of a European put option.
中文解析：
对于欧式看跌期权，因为只能到期行权，他在t时刻的value就是Max[0, X/(1 + r)T -St]，如果股票分红增加，分红派息会导致股票的每股净资产减少，所以股价必然下跌。另外由于股票分红时一般会进行除权处理，导致股价降低。那么St就会减小，从而期权的value会增加。
另外，从公式可以看出，无风险利率上升，分母变大，会导致期权价值减少。
持有成本增加，会导致标的资产价格上升，即St增加，所以会减少看跌期权的价值
St为啥增加呢，啥原理啊。谢谢
