The upper bound of a call value
A. underlying's price
B. underlying's price minus the present value of its exercise price or zero, which is greater.
我一直不明白, 我认为call value的最小值是0, 最大值是underlying price - exercise price, 如果考虑时间价值的话,那就是PV of (S - X). 但是这道题选择A. 这怎么回事呢?
