Answer:
The correct answers are b) and d) because only in these two options can you see the same sound present in several words, and that is the definition of alliteration. For instance:
b) And start their silent swinging, one by one.
d) Black reapers with the sound of steel on stones.
As it happens with the presence of the "s" sound in these words, the objective of alliteration is to highlight the words that possess the repetitive sound to enhance their meaning.
