The fictional dialogue James Madison created in "Who Are the Best Keepers of the People's Liberties?" supported which of the following conclusions?
A. Political factionalism was becoming more widespread as the United States entered the 19th century.
B. Leaders in the 19th-century United States subscribed to largely the same political doctrine.
C. Constitutional authority over individual American regions was still under dispute during the 19th century.
D. Republican philosophy was based on support for increased federal power during the 19th century.