For two American options that differ only
题型：单项选择题
问题：
For two American options that differ only in time to expiration, pest statement we can make is that :()
A. the longer-term option must be worth more than the shorter-term option.
B. the longer-term option must be worth less than the shorter-term option.
C. the longer-term option must be worth at least as much as the shorter-term option.
