The figure of speech Alliteration ("letters of alphabet") is a stilistic device, and it is defined by the <em>repetition of the sound of the initial letters in a</em> <em>sequence of words</em> (it can be consonants or vowels, or even different letters that have the same sound. Example: Phillip's feet ). In the poem, the words in option D present alliteration with the repetition of the sound <em>s </em>: silver; stream.