Congress wishes to incentivize the purchase of automobiles that have low emissions. It realizes that to create a market, enough hybrids and plug-in electric cars have to be sold for manufacturers to realize economies of scale and begin to reduce the prices of the cars. Congress, therefore, passes legislation that imposes a $10,000 environmental mitigation fee on the purchase of cars powered by internal combustion engines. The legislation prohibits reducing the sales price of cars to mitigate the cost to the purchaser. The revenue from the fee is collected by the Environmental Protection Agency, which uses it to subsidize alternative energy projects. Carmakers and dealers challenge the constitutionality of the fee in federal court. Which of the following would be least useful in defending the constitutionality of the fee?
a) The environmental mitigation fee is a valid exercise of Congress's taxing power
b) The fee is necessary to address a compelling government interest in reducing carbon emissions
c) Congress has the authority to regulate interstate commerce, including the automotive industry
d) The fee restricts economic freedom and should be struck down as unconstitutional