The correct answer is D. They are relieved that Grendel is dead and their trials are over now.
The monster Grendel has been ravaging the Danes' lands for so long, killing their men. This continued until Beowulf, a famous hero, was called for aid. He came, managed to kill the monster, and liberate the Danes from their threat. So obviously they were happy because they didn't have to be afraid of the monster anymore and they were grateful to Beowulf for saving them.