In my opinion, the correct answer is <span>B: "He asked himself where it had come from and how; the past provided no explanation, and the future could not justify it." This is the only instance when the main character tries to discover the source or roots of his happiness and infers that it hasn't resulted from any action from the past, nor from anything that might yet happen. The other options present this happiness as something that is almost a burden to him, and that's why they are examples of dark humor.</span>