Environmentalist: An increased number of oil spills and the consequent damage to the environment indicate the need for stricter safety standards for the oil industry. Since the industry refuses to take action, it is the national government that must regulate industry safety standards. In particular, the government has to at least require oil companies to put double hulls on their tankers and to assume financial responsibility for accidents. Industry representative: The industry alone should be responsible for devising safety standards because of its expertise in handling oil and its understanding of the cost entailed. Implementing the double-hull proposal is not currently feasible because it creates new safety issues. Furthermore, the cost would be burdensome to the industry and consumers. Which one of the following is an assumption on which the argument of the environmentalist depends? ['Government safety regulations are developed in a process of negotiation with industry leaders and independent experts.', 'Environmental concerns outweigh all financial considerations when developing safety standards.', 'The requirement of two hulls on oil tankers, although initially costly, will save money over time by reducing cleanup costs.', 'The only effective sources of increased stringency in safety standards for oil tankers are action by the industry itself or national government regulation.']