Answer:
B) knight, sedge, woe-begone, steed.
The author goes over a "knight at arms" alone, and clearly biting the dust, in a field some place. He asks him what's happening, and the knight's answer takes up whatever is left of the sonnet. The knight says that he met a delightful pixie woman in the fields.
He began spending time with her, making bloom festoons for her, letting her ride on his pony, and by and large being a tease like knights do. At long last, she welcomed him back to her pixie cavern. Sweet, thought the knight.
After they were through kissing, she "hushed" him to rest, and he had a bad dream pretty much every one of the knights and lords and sovereigns that the lady had recently enticed – they were all dead. And after that he woke up, alone, in favor of a slope some place.