Private industry is trying to attract skilled research scientists by offering them high salaries. As a result, most research scientists employed in private industry now earn 50 percent more than do comparably skilled research scientists employed by the government. So, unless government-employed research scientists are motivated more by a sense of public duty than by their own interests, the government is likely to lose its most skilled research scientists to private industry, since none of these scientists would have problems finding private-sector jobs. Which one of the following is an assumption on which the argument depends? ['The government does not employ as many research scientists who are highly skilled as does any large company in the private sector which employs research scientists.', 'Research scientists employed in the private sector generally work longer hours than do researchers employed by the government.', 'Government research scientists are less likely to receive acknowledgment for their research contributions than are research scientists in the private sector.', 'The government does not provide its research scientists with unusually good working conditions or fringe benefits that more than compensate for the lower salaries they receive.']