The correct answer here is A) Alliteration & Rhyme.
Alliteration is the repetition of the first sounds of several words in a row in one sentence. Here, alliteration can be seen in the word "silken" immediately followed by "sad".
Similarly, rhyme is the repetition of the same sounds occuring in several words in a row. Here, the most evident rhyme is in the words "uncertain" and "curtain".