Answer: I would contend that the right answer is actually the B) Alliteration.
Explanation: Just to elaborate a little on the answer, it can be added that alliteration is a poetic device that entails beginning two or more words with the same letter or sound. These words often tend to be in the same line. In this excerpt, the poet has repeated the letter b in four ocassions (barren, boughs, birds, and breeze), in order to make his poem more expressive.