The correct answer to this open question is the following.
Although there are no options attached we can say the following.
The problem-solving skill that is demonstrated in this case is "active listening" or "communication."
That is why, during the workshop, after much discussion, the girl was invited to speak and share her experience on the topic of bullying. Workshop attendants were open and willing to listen to what the girl had to say and it resulted very interested the degree that one participant suggested to consider her solution.
When students have to learn how to use the problem-solving process they learn to define a problem to determine its cause. This allows the student to have some alternatives, pick the right one and apply it. They consider options and evaluating them, comparing advantages and disadvantages in order to make the right decision.