The correct option is C Metaphor
'Metaphor' is a literary device / figure of speech in which a word or a phrase is given / applied to an action, object or event where it is not literally applicable. In simpler terms, a metaphor is a comparison that is drawn between two completely unrelated things. In this case, the speaker's sleep is compared to an ocean because of how calm and undisturbed it was; only to be interrupted suddenly - like how an ocean is aggravated during a storm, which cannot be literally true. Thus, the correct answer is Option C) - Metaphor. All the remaining options are also literary devices, but they have not been used in the given sentence.