Which of the Following Best Describes a Wave, in the Terrorism

Which of the following best describes a wave, in the terrorism context of the term?

A) It is a cycle of expansion and contraction phases, with internationally similar interests, causes, or goals.
B) It is seen when terrorists across the board wipe out their targets, like an ocean wave that eradicates sand castles on the beach.
C) It is when the flow of terrorism goes beyond what people can initially contain, but they may later overcome it.
D) Waves are periods of time in which terrorists gain enough support to form an army and challenge other nations head on.