It's definitely D.
It's for sure not C. And I've never read the full story, but this passage doesn't indicate a depressing mood of foreshadowing danger. And the vocabulary in the writing doesn't impact the story itself.
C
Saying The Opposite is saying the exact opposite same with B
Answer:
Because of the finite speed of light, when you gaze up into the night sky, you are looking into the past. The bright star Sirius is 8.6 light years away. That means the light hitting your eye tonight has been traveling for 8.6 years. ... When you look at that star tonight, you see it as it was at the time of your birth.
It is important for him because he wants to show the world that Beowulf is no hero and that Grendel's death is no heroic act. Just a lucky accident.