1. The problem asks to identify the worst catalyst from four energy vs. reaction progress graphs. 2. Each graph shows energy changes during a reaction: an initial rise to a peak (activation energy), then a drop to products. 3. The dotted curve represents the activation energy without a catalyst; the solid line shows the activation energy with a catalyst. 4. The effectiveness of a catalyst is judged by how much it lowers the activation energy compared to the uncatalyzed reaction. 5. The worst catalyst is the one whose solid line peak is closest to the dotted line peak, meaning it lowers the activation energy the least. 6. By comparing the graphs, the one with the smallest difference between the dotted and solid peaks represents the worst catalyst. 7. Therefore, the graph where the solid line peak is highest (closest to the dotted line) is the worst catalyst. 8. This analysis does not require exact numerical values but a qualitative comparison of peak heights. Final answer: The worst catalyst corresponds to the graph with the smallest reduction in activation energy, i.e., the solid line peak closest to the dotted line peak.