Why Was It So Important for Paul Ekman and His

Why was it so important for Paul Ekman and his colleagues to conduct research on the universality of facial expressions of emotion with the Fore tribe,an isolated society in the hills of Papua New Guinea?

A) It helped rule out the alternative explanation that people's facial expressions of emotion are based in genes.
B) It was necessary in order to know that cultural specificity in the ways emotions are experienced and expressed occurs even in isolated societies.
C) It helped rule out the alternative explanation that people learned facial expressions of emotion through exposure to Western culture.
D) It allowed them to show that blind individuals in different cultures are able to generate and understand the same facial expressions of emotion.