Answer:
D. purpose of article: The purpose of article is the reason about why the article is written, its importance and objectives. In scientist context, describing directly or indirectly the purpose of an article has a big impact, because you are using an objective writing due to the defined purpose. So, among the options purpose of article is the right choice.
C. 14-year-old girls: During this year, girls are too affected when they are being bulled. They cannot take that much pressure on them. The 13 years old boys are also affected, but they tend to be less emotional about it, also boys tend to seek justice by their hands, which allow them to release some pressure. Of course, the right choice in these cases is to inform to a authority to take care.
B. calling names: calling names can be an example of violence escalating if implies a discriminatory and derogative meaning. This action can make people more angry than usual, raising their impulse to attack in a violent way.