Answer:
It's C because the south was trying to gain to gain greater power in the House of Representatives. they were not however trying to end slavery as quickly as possible because you have to remember the south was all for slavery (they literally depended on it ), not against it, that would be the North. Also the south treated slaves very poorly and thought of them as the dirt beneath their feet, or the lowest of the lowest class, so they would not want them to receive any political rights or want their slaves to think, or be thought of to be equal to whites. They did not demand passage of the Three-Fifths so that they could defeat the Union in the civil war either since that passage has nothing to do with the civil war . So again this leaves you with C.
hope this helps :)