Proposed new safety rules for the Beach City airport would lengthen considerably the minimum time between takeoffs from the airport. In consequence, the airport would be able to accommodate 10 percent fewer flights than currently use the airport daily. The city's operating budget depends heavily on taxes generated by tourist spending, and most of the tourists come by plane. Ttherefore, the proposed new safety rules, if adopted, will reduce the revenue available for the operating budget. The argument depends on assuming which of the following? ['Few, if any, of the tourists who use the Beach City airport do so when their main destination is a neighboring community and not Beach City itself.', 'If the proposed safety rules are adopted, the reduction in tourist numbers will not result mainly from a reduction in the number of tourists who spend relatively little in Beach City.', 'Increasing the minimum time between takeoffs is the only way to achieve necessary safety improvements without a large expenditure by the city government on airport enhancements.', 'The response to the adoption of the new safety rules would not include an increase in the number of passengers per flight.']