Answer:
The sentence reveals that:
A. Nick believes the East is a sophisticated place.
Step-by-step explanation:
The sentence suggests that Nick has a negative view of the Middle West, which he sees as the "ragged edge of the universe." In contrast, he sees the East as a place of opportunity and sophistication, where he can learn the "bond business." The phrase "warm center of the world" implies that Nick once saw the Middle West in a positive light, but his perspective has shifted. The contrast between the warm center and the ragged edge underscores the idea that Nick views the East as a more desirable and attractive place than the Middle West. Therefore, the sentence reveals that Nick believes the East is a sophisticated place.