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".
The answer is B. "Frightened."
You can draw the conclusion that the author is trying to communicate a frightened tone by the diction of the stanza. The following line of the text states: "In the silence of the night, How we shiver with affright..." This is a very telling detail that supports the idea that the author's tone was meant to be frightening.
The correct answer is D, because there are three independent clauses in this sentence, all of the clauses are independent. A means that there is at least one dependent clause, which is not the case here, and B means the same. C mean that there is only one independent clause in the sentence.
