Without being able to see the specific cartoon "Le peuple sous l'ancien regime," I can offer some insights based on common themes related to the French Revolution and social structures in pre-revolutionary France.
Typically, political cartoons of that era depicted the stark inequalities between the social classes: the First Estate (clergy), the Second Estate (nobility), and the Third Estate (common people, which included peasants, urban workers, and the bourgeoisie). Often, the Third Estate was shown as bearing the burdens of taxation and labor while the First and Second Estates enjoyed privileges and power.
Considering these themes, the best response would likely be:
The Third Estate supported the entire social structure.
This reflects the common interpretation that the Third Estate sustained the society and economy while being burdened with responsibilities and lacking power, highlighting the inequities leading up to the Revolution. However, please review the actual cartoon for precise interpretation.