Read these sentences from the speech there is no negro problem. There is no southern problem. There is no northern problem. There is only an American problem. How do these sentences convey Johnson’s viewpoint ?

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:

the maximum speed limit is 55 mph on a two-lane undivided highway and for vehicles towing trailers.