At her husband’s funeral, Elaine noticed that her son did not talk much to the other mourners and did not show any outward signs of grief. Elaine knows that visible grief isn't always a sign that grief is more intense. She knows her son misses his father. Overall, the funeral demonstrated that some aspects of how people demonstrate emotions are dictated by society and have been learned from childhood. In this case, Elaine has been observing which of these?
a. thought suppression
b. facial expressions
c. rumination
d. display rules