Mary Cassatt, oil painting, she might have considered what medium would be able to blend well for the skin, but also have realistic texture. another advantage she might’ve considered is oil paint dries so slow that you have time to go back days later and fix any mistakes or touch up something that went unnoticed before. disadvantages could be not enough definition because oil paint blends too well and oil paint dries very slow so she would have to wait for long periods of time to layer the paint if she needed to.