Editorialist: The positions advanced by radical environmentalists often contain hypotheses that are false and proposals that are economically infeasible. But there is a positive role to be played even by extremists, for the social and political inertia that attends environmental issues is so stubborn that even small areas of progress can be made only if the populace fears environmental disaster, however untenable the reasons for those fears may be. Which one of the following most accurately expresses the main conclusion of the editorialist's argument? ['Radical environmentalists advocate positions without regard for factual support or economic feasibility.', 'Radical environmentalists often put forth untenable positions in order to produce the fear that is required to bring about moderate reforms.', 'Radical environmentalists, by promoting their views, stimulate progress on environmental issues.', 'Social and political inertia is most effectively overcome by an extremely fearful populace, regardless of whether its fears are well-founded.']