Read the excerpt below and answer the question.

"I reached the crag of Scylla and dire Charybdis’ vortex
right when the dreadful whirlpool gulped the salt sea down."

What is the comparison that is being made in this passage?

Scylla is being compared to a whirlpool.
Odysseus is trying to avoid being drowned by Charybdis.
Charybdis is being described as a human who can "gulp".
Charybdis is a six-headed monster.