D) A savage beguiler
In sheathings of silk
The lines chosen must show that the sea is cruel but it seems as though it's not. The word beguile means to enchant something in a deceptive way. By describing the sea as a savage beguiler, it gives the sea the image of something that is fierce, but not seen as fierce. It's seemingly calm beauty, like silk, tricks one into thinking that it is calm.
The other options do not work. Option A only creates a negative image. Option B also only creates a negative image of the sea as a predator. Option C personifies the sea as having fingers, but doesn't show it's cruel nature.
