I have never read what you are asking, but just by looking at it, I would assume that he is stereotyping Dutch people, because he is calling Black Dog an insult, which is "son of a dutchman".
I just answered, the correct is the persecution felt by jewish people,such as kafka, in eastern europe. (D)
I’ve never read the novel but u can ask google or insert an image of text
Answer: B
Explanation: That should be the right answer, I hope I'm correct.