Answer:
C the September 11 ,2001 terrorist attacks
This is an example of imitation/copying.
Imitation is a way of behavior where an individual<em> observes and replicates the behavior of others.</em> It is a reproduction of an act that is simulated by the perception of a similar act by another animal or person.
To imitate/copy somebody or something a model is needed. The copying may be done none-consciously ( seeing and copying others without thinking about the reason to do it ,) or it can be a conscious strategy ( out of uncertainty how to act or behave in some situation).
In Libby's case, the act of imitation<em> comes as a conscious process of wanting to behave correctly</em> and to fit in with others.The other students are Libby's model to copy her behavior from.
