I guess cause they are so close.
I believe the answer is: C a creation of a more national unified American trading economy
The core strategy behind the American system is to increase the tariff that imposed to foreign products when they enter united states. By doing this, Clay hoped to create a unified American trading by making it easier for local Small businesses to compete.
Irredentism
"Irredentism is any political or popular movement that seeks to claim/reclaim and occupy a land that the movement's members consider to be a "lost" territory from their nation's past. Wikipedia"
Political differences created distrust among the Whites and prevented them from cooperating effectively with one another, some Whites insisted on restoring the czarist regime, others believed that only a more liberal and democratic program had only chance of success, and the Whites, then, had no common goal. The communists, in contrast, had a single-minded sense of purpose.
hope this helps ^-^