Answer: A. the simplicity and beauty of middle-class life.
Explanation:
This painting is representing the simplicity and beauty of middle-class life and also important, everyday life of one maid in France. This is simple work that is representing how the maid is feeling after coming back from the market. Her face is plain but also we cannot see any stress from it and that is why this painting is representing the beauty of normal and everyday life.
That is why other answers are not correct, it does not represent any struggle or something bad and poor about her life.