The Third Party System Ended When One Issue Declined in Importance,and

The third party system ended when one issue declined in importance,and the fourth party system began when focus shifted to a different set of issues.This illustrates:

A) that partisan divisions reflect societal divisions over what government should do
B) how parties ended debate over the social issues in the United States
C) how parties can disintegrate and be replaced by new ones
D) the enduring importance of race in American politics
E) how parties ignore the nation's most pressing problems to avoid controversy and maintain their own power