It basically translates to "Be at your best behavior!" or "Be ready at attention" depending on the scenario.
The motif of marigolds is juxtaposed to the grim, dusty, crumbling landscape from the very beginning of the story. They are an isolated symbol of beauty, as opposed to all the mischief and squalor the characters live in. The moment Lizabeth and the other children throw rocks at the marigolds, "beheading" a couple of them, is the beginning of Lizabeth's maturation. The culmination is the moment she hears her father sobbing, goes out into the night and destroys the perfect flowers in a moment of powerless despair. Then she sees the old woman, Miss Lottie, and doesn't perceive her as a witch anymore. Miss Lottie is just an old, broken woman, incredibly sad because the only beauty she had managed to create and nurture is now destroyed. This image of the real Miss Lottie is juxtaposed to the image of her as an old witch that the children were afraid of. Actually, it is the same person; but Lizabeth is not the same little girl anymore. She suddenly grows up, realizing how the woman really feels, and she is finally able to identify and sympathize with her.
Answer for part A:
He uses a metaphor to suggest that white people have proven themselves unworthy of the authority they wield.
Answer for Part B:
It suggests that their deceitful acts are intentional.
I took the test
