The government has proposed a plan requiring young people to perform services to correct various current social ills, especially those in education and housing. Government service, however, should be compelled only in response to a direct threat to the nation' s existence. For that reason, the proposed program should not be implemented. Which one of the following is an assumption on which the argument depends? ["Some of the social ills that currently afflict the nation do not pose a direct threat to the nation's existence.", "The nation's young people believe that current social ills pose no direct threat to the nation's existence.", 'Government-required service by young people cannot correct all social ills.', "Crises in education and housing constitute a threat to the nation's existence."]