Answer: A) Alliteration.
Explanation: alliteration is a literary device that consists in the repetition of the beginning sounds of consecutive words, or words that are close to each other, in order to create an impact on the reader. In the given sentence we can see an example of alliteration, because of the repetition of the "f" sound in the words "foxes," "fled," "foes," "forests," and "fens." So the correct answer is the corresponding to option A.
