There is no doubt ______ international cooperation is key to ______ with cybercrime, as

Vinton Cerf has said that the problem of cybercrime is _______ huge that it requires UN

to form a special agency to act as an international referee or steward. [ ]

A. whether ; doing ; so

B. that ; dealing ; so

C. whether ; dealing ; such

D. that ; doing ; such

超声波检测法是利用超声波在材料中的（），（），（）等传播特性变化来发现缺陷的。