Dr. diaz is a researcher studying emotions. specifically, diaz is

Dr. Diaz is a researcher studying emotions. Specifically, Diaz is interested in the behavioral expression of emotions. Her research program could involve any of the following EXCEPT
gestures used with various emotions in different cultures.
ethnic differences in tone of voice in response to joy.
gender differences in body postures in response to anger.
the approach-avoidance nature of emotions.
age differences in the appraisal of anger.