Answer:
A. alliteration
Step-by-step explanation:
Alliteration is a figure of speech in which the same consonant sound is repeated in the sentence. The initial syllable or the words with similar sounds appear in the same sentence. The repetition of the consonant sound appears in alliteration. In the given sentence, the words 'frightening', 'flap', 'feathered' begins with the same consonant sound 'f'. Hence, in this line alliteration has been used.