Helpful material. With thanks.
official website https://shallbd.com/understanding-the-maturity-period-of-options-and-how-it-affects-your-investments/
their explanation [url=https://shallbd.com/zh/zai-minitab-zhong-ji-suan-yi-dong-ping-jun-xian-de-bu-zou-wan-zheng-zhi-nan/]do you agree[/url]