The correct answer is "D".
A metaphor is a word applied to an object to which it is not literary applicable. These words "dead", "blood", "treacherous", "savage", "prey", "murdered", and "strangled", are being used as metaphors in the description of the ocean by the author. In other words, he is trying to transmit the message to the reader that this particular ocean is far from safe and the chances of navigating past it unharmed are very low.
