Answer:
The answer is indeed letter A. the rhythmic quality and repetition of certain words.
Step-by-step explanation:
Repetition as a rhetorical device - and as the name suggests - consisting of repeating a word or a group of words to produce emphasis, emotion, or clarity. In the excerpt we are studying here, what we have seems to be a mesodiplosis. Mesodiplosis consists of repeating a word in the middle of each phrase or clause. That helps create a certain rhythm. In this case, the emphasis is on the pronoun "we". The speaker intends to stress that everyone, with no distinction of race or gender, has helped form the Union.