Paper and plastic grocery bags are a continuing problem for the city, both as litter and in landfills. To discourage their use, the city has proposed a tax on each bag, to be paid by the supermarkets that supply them. Several environmental groups, however, oppose the tax, despite having brought the issue to the council' s attention in the first place. Which of the following, if true, would best explain the environmental groups' opposition to the proposed tax? ['Only supermarkets distributing more than a certain number of grocery bags each month would be subject to the proposed tax.', "Plastic bags account for 90 percent of the grocery bags that litter the city's streets and take up space in landfills.", 'The cost to the city of collecting and disposing of a grocery bag is greater than the proposed tax per bag.', 'Supermarkets plan to pass the tax on to consumers, who are unlikely to change their behavior based on the small increase in their grocery bills.']