Answer:
In my opinion, the correct answer is clarity. By using the repetition, the author tries to clarify what this problem isn't - by its nature it isn't Negro, Southern, or Northern. And then, he affirms what it is - it is American. Therefore, he says that compartmentalizing this problem is not going to help. People have to understand it for what it really is - everyone's problem, the problem of the nation itself.
Explanation:
