Identify the figure of speech used in the following expression:“The s…

The correct answer is Option (3) → Personification

Personification:

• It gives human qualities, feelings or actions to things that are not human.
• This expression: the ocean waves are called "savage" and "cruel", words for the nature of a person, and they "roar" like a living creature.
  Example: The angry storm tore the roofs off the huts.

Why the Other Options are Incorrect?

Option 1: Apostrophe — Incorrect. Apostrophe is a direct address to someone absent or to a thing or idea, usually beginning with "O". The waves are described here, not spoken to.
Example: "O Sea, take my boat safely home."

Option 2: Transferred Epithet — Incorrect. A transferred epithet moves an adjective from the person it describes to a thing connected with that person, as in "sleepless night" (the person, not the night, was without sleep). "Cruel waves" gives the waves a human quality of their own, so it is personification.
Example: He spent a sleepless night before the examination.

Option 4: Metaphor — Incorrect. A metaphor says that one thing is another to compare them, without "like" or "as". The expression does not call the waves something else.
Example: Time is a thief that steals our youth.

Contrast: personification gives a thing human qualities of its own (cruel waves); a transferred epithet moves an adjective from a person to a thing connected with that person (sleepless night).