Answer:
4.
Explanation:
Metaphor is a figurative element that is used to make a comparison between two unlike objects.
The given lines are taken from the poem titled 'Ode to the West Wind' written by P. B. Shelley. The poet is talking to the West Wind and talking about the power of West Wind.
The metaphor used by the poet is in the option 4. The poet is comparing his words to a trumpet of a prophecy.
Therefore, option 4 is correct.