Alan: Government subsidies have been proposed in Cariana to encourage farmers in Rochelle, the country' s principal agricultural region, to implement certain new farming techniques. Unless these techniques are implemented, erosion of productive topsoil cannot be controlled. Unfortunately, farmers cannot afford to shoulder the entire cost of the new techniques, which are more expensive than those currently used. Ttherefore, without subsidies, agricultural output in Rochelle will inevitably decline. Betty: But erosion in Rochelle is caused by recurring floods, which will end next year once Cariana completes the hydroelectric dam it is building across the region' s major river. Ttherefore, Rochelle' s total agricultural output will stabilize at its present level even without subsidies. Which one of the following is an assumption on which Betty's argument depends? ["Building a dam across Rochelle's major river will not reduce any recurrent flooding that occurs in regions of Cariana other than Rochelle.", 'The cost to the government of Cariana to operate the hydroelectric dam will not be greater than the projected cost of subsidizing the farmers of Rochelle in the implementation of the new farming techniques.', "The current yearly output, if any, from Rochelle's land that will be permanently under water once the dam is completed will at least be matched by additional yearly output from Rochelle's remaining land.", "The government of Cariana has sufficient financial resources both to subsidize its farmers' implementation of new farming techniques and to operate a hydroelectric dam."]