The student presents three diagrams, one illustrating the negative production externality of petroleum, oil, and energy, and the other two demonstrating how the externality was reduced through carbon taxes, all of which are relevant to the article. However, it is mentioned that two diagrams would be sufficient to score full marks. Additionally, all diagrams are correctly labelled with axes annotated in connection to the article. On the other hand, the explanations provided alongside the diagrams need to be clearer, specifically indicating the curve shifts from MPC to MPC+tax towards the socially optimum level. As of now, the reader does not know which curve shifts and where they shift.
