Hello, thanks for asking the question. 

You have a point saying that D shows the emotion of the narrator. He definitely is vexed - annoyed - and hates the engineer. However, the point is why he feels this way toward the engineer. 

In the beginning paragraphs of the passage, we know that the thing the narrator most wants is to work on a steam boat. He has rather naiive dreams about how "cool" it would be to work on a boat. And then, the engineer appears and "shook the bottom of the (narrator)'s sunday school teachings" By this we know that the reason the narrator hates the engineer so much is because the engineer's life is exactly what the narrator wants. We see that the narrator is blind with jealousy and envy. Therefore, the choice that mentions "envy" is the best for the answer. So, the answer is "animosity and envy".

Hope this helps.