What gave Lily the idea that the sisters knew about her mother?

What gave Lily the idea that the sisters knew about her mother?
A. She found an unusual brooch that looked like one her mother had owned.
B. She saw May luring roaches with marshmallows and crackers, like her mother.
C. She saw a place in the woods that was in a painting on her mother’s wall.
D. She heard June playing a song on the cello that her mother had sung to her.