Answer: C-The Cyclops’ effort to move the stone is compared to a simple task, showing his strength.
A simile is a figure of speech that compares two things directly by using connecting words (such as like, as, so, etc.). In this sentence, the sentence "as one would cap a quiver" is comparing how easy it would be for a person to cap a quiver with how easy it was for the Cyclops to move the stone. It is a way to express his enormous strength without mentioning it explicitly.