B. Variable currency based on the price of gold
I say C. because the entire paragraph is talking about political power.
There was great wealth in the South, but it was primarily tied up in the slave economy<span>. In 1860, the </span>economic<span> value of slaves in the United States exceeded the invested value of all of the nation's railroads, factories, and banks combined. On the eve of the </span>Civil War<span>, cotton prices were at an all-time high.</span>