The answer is option “B”: It implies that the challenge was not fearless, but timid.
Grendel is a novel written by the American author John Gardner. The story is based on the Old English poem Beowulf, written by an unknown author. Although the story derives from a heroic poem, which tells the story of the great warrior Beowulf, Gardner’s version focuses on an existentialist view of Beowulf’s antagonist, the monster Grendel. In the passage given, Grendel, who, as a child, used to live inside a cave with his mother, exits the underground and reaches the surface, under the moonlight. This is a new world to Grendel, who was used to live in the darkness of the cave, therefore, he starts to explore this new world with great precaution.