NO.PZ2023091802000123
问题如下：
Looking at a risk report. Mr. Woo finds that the options book of Ms. Yu has only long positions and yet has a negative delta. He asks you to explain how that is possible. What is a possible explanation?
选项：
A.
The book has a long position in up-and-in call options.
B.
The book has a long position in binary options.
C.
The book has a long position in up-and-out call options.
D.
The book has a long position in down-and-out call options.
解释：
As the underlying assets’ price increases the up-and-out call
options become more vulnerable since they will cease to exist when the barrier
is reached. Hence their price decreases. This is negative delta.
为什么delta大于0？
