（1分20秒-1分50秒）And as you look at what went on，the problem wasn'；t that there was a system that didn'；t work well enough，the problem was that（）.
A.We didn’t have a surveillance system
B.We didn’t have a control system
C.We didn'；t have a system at all.
D.We didn’t have a response system
正确答案：We didn'；t have a system at all.