With the exception of the last sentence, all sentences are fluidly written and clearly connected between each other. In the case of the last example, the lack of transitional phrases between the two sentences creates a disconnection between the concepts expressed. While we might still be able to understand these sentences, we need to make the transition happen for ourselves as it was not included in the example.
Therefore, your best answer is option D.
Your answers correct. It's true
All legislative Powers herein granted shall be vested in a Congress of the United States, which shall consist of a Senate and House of Representatives.