GRE Reading Comprehension: ETS-GRE阅读ETS - 56RXR3PDJ22HLZXP7

Which one of the following circumstances would most seriously undermine the conclusion "Such a tax would induce industry to substitute less-polluting fuels for those carrying a higher tax" A. The fuel taxed a the highest rate costs considerably less to buy than fuels taxed at lower rates. B. The goal set by the Toronto Conference cannot be reached unless each fuel it taxed at a much higher rate. C. The tax on coal represents a much greater cost increase than does the tax on oil or gas. D. It is discovered that gas produces even less carbon dioxide per unit of energy generated than was previously thought. E. It is discovered that coal produces even more carbon dioxide per unit of energy generated than are previously thought.