关于calendar spread这题，请老师解析一下

问题如下：

Based on Exhibit 1, the best explanation for Nuñes to implement Strategy 5 would be that, between the February and December expiration dates, she expects the share price of XDF to:

选项：

decrease

remain unchanged

increase

解释：

Correct Answer: C

C is correct. Nuñes would implement Strategy 5, which is a long calendar spread, if she expects the XDF share price to increase between the February and December expiration dates. This strategy provides a benefit from the February short call premium to partially offset the cost of the December long call option. Nuñes likely expects the XDF share price to remain relatively flat between the current price €74.98 and €80 until the February call option expires, after which time she expects the share price to increase above €80. If such expectations come to fruition, the February call would expire worthless and Nuñes would realize gains on the December call option.