I would say that Thoreau most clearly uses B. Parallelism. It is the use of grammatically similar structures. In this case, the parallelism is additionally underlined with the use of the same vocabulary. "<span>It not only divides States and churches, it divides families; ay, it divides the individual" - Thoreau uses clauses with predicates in simple present tense, and the same verb - to divide. </span>
