The quote is all about nature, and D is the only one about nature, so I'd say that's the best answer.
Answer: Allusion
Explanation: An allusion is a literary device used to reference another object outside of the work of literature. The object can be a real or fictional person, event, quote, or other work of artistic expression.
This passage has a melancholic mood. You can tell this due to some specific key words: "dull", "dark", "soundless." They all have a negative connotation. The imagery of a lone rider in a dreary and dull country under the oppressive sky may clue you in that the overall passage has a sad tone to it. Even later in the passage the author states that the scene is melancholic.
Their living room is painted a bright, shiny red.
The answer is threatening (I got it correct on the test)