Assuming that the question is related to Abraham Lincoln´s 1865 speech, in the Second Inaugural Adress, in short words, what he is trying to say is that if difficulties come from God, is because there is something wrong that should be corrected, that there is something that needs to be fixed, therefore, the evidence that he quotes is that slavery as it is something wrong in the sense that it was one of the reasons for war, then it needed to be corrected, the war was the way to fix this matter.
Answer is B. While the language he used was still considered modern English, he invented his own words which makes it confusing to understand for modern students.
Colons are used after complete sentences, and what comes after the colon should give more information on what came before it. Knowing this information, A can be ruled as the correct answer.