The Study of a Woman's Back was created by B. Henri Matisse. He was the painter who drew a lot of sketches and paintings of women's backs because he was fascinated by them. It cannot be any of the other painters because their styles differed so much: Renoir painted realistic paintings, Duchamp was more of a sculptor, and Seurat used the technique of pointillism, all of the characteristics which are not visible in this painting.
Yup i would do a test on them i would tell a lie about myself and see if they will stay or leave. If they stay then they true friends if they leave then they fake