C, a mystery because the sea holds many unknowns
B, because snarling is not associated with something loving/nice but it also doesn't indicate something challenging. It's simply an image of something angry/evil
I would say "personification" and it seems to be used in the following passages, "joy whose hand is ever at his lips, and bidding adieu", "turning to poison while the bee-mouth sips"," Veil'd melancholy has his sovran shrine" and finally " his soul shall taste the sadness of her might". So joy is personified as being a hand at lips, the mouth like a bee (local simile) that sips, melancholy is like a person that has his shrine, and a soul can taste sadness.
