The simile "teeth white as milk" found in the second stanza of the poem most likely refers to C. the foam on the waves.
The man in the moon makes no sense, since the poem is talking about the sea. A great white shark would be a silly answer. The darkness of the sea is also incorrect because that can't be white if it's dark. So, the foam on the waves, which is white, by the way, is the correct answer.
