C. because of the desire of many to abolish slavery
Republican Party was founded in Wisconsin in 1854, to oppose the spread of slavery into the western territories of USA.
southerners, for their part, considered brown a terrorist. they felt threatened by northerners' deification of brown and worried about the potential for other, similar armed insurrections.
it was the "4. potsdam" conference that demanded the unconditional surrender of japan, since it was clear that the japanese would continue to find until the very last man otherwise.