The best response to how the cat’s motivations advance the plot is:
The cat’s determination to bring interesting news to the other animals causes him to embellish and lie about something and set the plot in motion.
This choice reflects the cat's desire to impress the other animals with his knowledge, which leads him to present the painting in an exaggerated and misleading manner. This embellishment ignites the animals' curiosity and excitement, setting the stage for further developments in the story.