Lincoln declared that they would have to accept the amendments and the new government, disband their old confederate government, make sure that former office holders could never go back into politics, and ask for an official pardon from the President of the United States. They also had to free the slaves.
It would be C. It gave them the rights to vote for representation in the government.
It helps us better understand the choices of the people before us. If we don't learn about its history then the lives lost fighting would be worthless.