The information presented in Table 1 shows millions of metric tons of sulfur dioxide emitted by high-income nations over the past sixty years. According to proponents or supporters of environmental Kuznets curve theory, what factor explains why this pattern exists: Table 1. Sulfur Dioxide Emissions by Decade in High-Income Nations Year Millions of Tons 1950 500 1960 625 1970 774 1980 805 1990 997 2000 743 2010 656 Question 2 options: Increased amounts of time spent commuting by car in high-income nations during the period The shift of economic activity from agriculture to manufacturing to services in high-income nations during the period The race to the bottom Both a and b Both b and c