The poetic device that Yeats used in the underlined portion is that of A. alliteration - repetition of beginning sounds of words in close proximity.
Yeats used alliteration when he used foolish and full because both of them are pronounced in a similar way at their beginnings.
Alliterations are best noticed when the similar words are fused close to each other as foolish and full were used.
Find out more on alliteration at https://brainly.com/question/536028.
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