Which excerpt from "Keynote Address" is an appeal to timeliness? "It has built the schools in which they are being educated to higher levels than ever in our nation’s history." "But let us resist also the temptation of apathy because we can never cure the causes of violence with indifference." "We are here tonight because in large part we share our faith in our country and in its processes of orderly, humanistic change." "Let us welcome the ideas and energies of the young and the talents and participation of all responsible people."