6. The author of this passage is concerned primarily with
(A)suggestion an appropriate role for third parties in U.S. politics
(B) discussing the decline of third-party movements in U.S. history
(C) explaining why third-party movements in the U.S. have failed to gainnational power
(D) describing the traditionally non-ideological character of U.S. politicalparties
(E) suggesting ways in which peripheral parties may increase their influence