Politician: Governments should tax any harmful substance that is available to the general public at a level that the tax would discourage continued use of the substance. Which one of the following is an application of the politician's principle of taxation? ["The tax on products that emit fluorocarbons, substances that have proven to be harmful to the earth's ozone layer, is lowered to stimulate the development of new, less environmentally harmful ways of using these substances.", 'The tax on certain pain relievers that, even though harmful, are available over the counter is raised, since studies have shown that the demand for these products will not be affected.', 'The tax on domestically produced alcoholic beverages is not raised, since recent studies show that the tax would have a negative impact on the tourist industry.', 'The tax on a pesticide that contains an organic compound harmful to human beings is raised to give people an incentive to purchase pesticides not containing the compound.']