Certain politicians in the country of Birangi argue that a 50 percent tax on new automobiles would halt the rapid increase of automobiles on Birangi's roads and thereby slow the deterioration of Birangi's air quality. Although most experts agree that such a tax would result in fewer Birangians buying new vehicles and gradually reduce the number of automobiles on Birangi's roads, they contend that it would have little impact on Birangi's air-quality problem.

Which of the following, if true in Birangi, would most strongly support the experts' contention about the effect of the proposed automobile tax on Birangi's air-quality problem?

• AAutomobile emissions are the largest single source of air pollution.  
• BSome of the proceeds from the new tax would go toward expanding the nonpolluting commuter rail system.  
• CCurrently, the sales tax on new tax on new automobiles is considerably lower than 50 percent.  
• DAutomobiles become less fuel efficient and therefore contribute more to air pollution as they age.  
• EThe scrapping of automobiles causes insignificant amounts of air pollution.