What literary device does the writer use in the couplet?

To accurately identify the literary device used in the couplet you provided, I would need to see the actual couplet in question. Each of the options you listed—irony, metaphor, pun, and personification—represents a different literary device:

a. **Irony** - A contrast between expectation and reality.
b. **Metaphor** - A direct comparison between two unlike things without using "like" or "as."
c. **Pun** - A play on words that exploits multiple meanings for humorous or rhetorical effect.
d. **Personification** - Attributing human characteristics to non-human entities.

If you can provide the couplet, I can help determine which literary device is being used!