The city of Workney, in raising bus fares from $1. 00 to $1. 25, proposed that 18 fare tokens be sold for $20. 00 to alleviate the extra burden of the fare increase on the city' s low-income residents. Critics suggested alternatively that 9 fare tokens be sold for $10. 00, because a $20. 00 outlay would be prohibitive for low-income riders. The alternative proposal depends on which of the following assumptions? ['Low-income residents of Workney will continue to ride the buses in the same numbers despite the fare increase.', 'Buses provide the only means of public transportation in the city of Workney.', "The proposed fare increase is needed for the purchase of new buses for the city's bus system.", 'The outlay of $10. 00 for the purchase of 9 fare tokens would not be prohibitive for low-income bus riders.']