The answer to this question is A
The answer is B. "He asked himself where it had come from and how; the past provided no explanation, and the future could not justify it."
This option is not a dark humor because it does not show the opposite side of happiness. The other choices explain that although there is happiness, he considered it as a burden- making it a dark humor.
Could be the last three tbh one of those
D is the correct option :)
Hope it helps :)