What best explains the development of Madame Defarge?

This question sounds as if there should be answers attached..... which "best" explains the development?

Madame Defarge becomes increasingly crazed as the tale moves from start to finish. Her thoughts and actions are no longer seen as those of someone interested in a revolutionary cause, but rather those of a madwoman.

In Chapter 12, Dickens provides Madame Defarge, his villain, with ample justification for her angry actions, though he subtly criticizes their performative nature. As Carton eavesdrops on her in the shop, she bares her secret to her friends, and her disclosure causes her readers "to derive a horrible enjoyment from the deadly nature of her wrath." The wrongs committed against the French lower classes, as demonstrated by the actions of the St. Evremonde family, were very real, and the impetus to class struggle has been justified. It is the escalation of the terror to a performance, with all its unreal inhumanity and extended suffering, that alarms Dickens.

The important part of the aristocrat Foulon's death in Book II, Chapter 22, is not the fact that he is a human being who is dying, but the ritualistic stuffing of grass in his mouth. Madame Defarge claps for this death as she would clap for a play. In the same way, her audience appreciates her pain not as a human emotion but as an abstract dramatic phenomenon. The performative nature of the French Revolution was recorded by many onlookers, who noted that women like Madame Defarge would attend executions at the guillotine and chat with their friends and knit as if they were at a show.