Personally, I would write on limited government. You could talk about the foundation America was built on, and how families should have the sole rights to decide what to do in their homes and country, without being so affected by the government!!
With the increase of trade a new class of people devolved made up of merchants, traders, and craft workers. these people began to form an association called guilds.
John Stuart mill believed in checks and balances
I would say C just because he was helping more of the children's sake
Washington Gladden's ideas would most closely be tied to the period in U.S. history that begins just after the Civil War and leads into Reconstruction.