Among the Reasons American Government Is Now Much Harder to Administer

Among the reasons American government is now much harder to administer compared to the 18^th and 19^th centuries is that

A) the United States is 300 million diverse and free people,instead of 4 million people in a slave-holding society.
B) the United States is politically divided.
C) the 20^th century featured more consensus among the political elite.
D) Federalism has reduced the importance of the states.
E) there are fewer interest groups participating in government today.