Final answer:
The activity that is NOT cyberbullying among the choices is posting a message expressing disagreement with someone's opinion, as true cyberbullying entails repetitive and intentional actions meant to cause distress.
Step-by-step explanation:
Cyberbullying is a form of harassment using electronic forms of contact. In the context of the question asked, cyberbullying involves repeated and intentional actions meant to harm others using digital platforms. It can range from sending threatening messages to posting embarrassing images or spreading rumors online. Examples include pretending to be someone else on social media to humiliate them, posting public threats, or repeatedly targeting someone with negative comments. However, simply posting a message disagreeing with someone's opinion does not constitute cyberbullying if it is not part of repeated harmful behavior.
The final answer to the question is: Posting a message saying that you disagree with someone is NOT an example of cyberbullying. This is because cyberbullying involves repeated, intentional harm, which differs from expressing a single, potentially polite disagreement.