The best answer would be A. pre: first
Well it is not stop listening, or make an effort too attend, I am sure that assign meaning is correct.
The impact of Keats's repetition of the word what is that he wants to express the thoughts of the people on the urn. In this way, it will be easier to understand what the people are trying to mean with the urn.
It means to give credit to the author and source. It helps in an argument because when you're trying to prove a point, you have to have factual evidence that proves you're right.