Final answer:
The subject of Jacques-Louis David's painting, The Oath of the Horatii, exhibited at the Salon of 1785, is defending the family and city/state structure.
Step-by-step explanation:
The subject of Jacques-Louis David's painting, The Oath of the Horatii, exhibited at the Salon of 1785, is Defends the family and city/state structure. In the painting, the three Horatii brothers are shown taking an oath to defend their city and fight for their country. The painting conveys the idea that one must be willing to sacrifice, even sacrificing one's life and family members, for the state.