The correct answer is B) writing a Constitution.
The action that accomplished all the goals of the French Revolution is the writing of a Constitution.
Since the beginning of the movement, French people wanted to eliminate the absolute power of the monarchy and the influence of the Nobles. French people lived in poverty and suffered so much for lacking the basics. They wanted better laws and the creation of a Constitution would allow that to happen and overturn the injustice lived until that moment. So it is true that the action that accomplished all the goals of the French Revolution is the writing of a Constitution.