The correct answer is “the poet’s fondness for abstract ideas.”
When Samuel Jonson coined the term “metaphysical poets”, the trait he was calling attention to was the poet’s fondness for abstract ideas.
Samuel Johnson –a renown critic- coined the term “metaphysical poets” to refer a group of English poets in the 17th century that used abstracts ideas or “beyond physics” ideas in their writings. Among those poets, the most famous metaphysical authors were John Donne and John Dryden.
The other options of the question were, a) the poet’s incorporation of nature imagery, b) the poet’s imagination of euphoric sounds, and d) the poet’s interest in philosophical questions.