According to Ekman's Research on Facial Expressions

According to Ekman's research on facial expressions:

A) when people try to hide their feelings with an inauthentic expression, they use different groups of muscles than they do for authentic emotions.
B) when trying to feign sadness, only about 60% of people manage to get the eyebrows, eyelids, and forehead wrinkle exactly right.
C) there is little support for Darwin's evolutionary explanation that certain human facial expressions are "wired in."
D) authentic smiles last 10 seconds or more, whereas false smiles last only about 2 seconds.