Q11. (ch5) Vollebergh et al. (2009) find evidence for the Environmental Kuznets Curve (EKC) for sulfur dioxide emissions in a panel of OECD countries. Based on the finding of the paper, answer the following sub-questions. a. Fill in the blank: the pollution is a(n) good before income hits the certain threshold and a(n) good after. b. Their economic analysis has some caveats (discussed in the paper). Describe them briefly using the keywords provided for each. Effective central authority I More efficient production process, not actual demand