Why Would an Evolutionary Psychologist Be Concerned with the Issue

Why would an evolutionary psychologist be concerned with the issue of personality variations in humans and non-humans?

A) because the establishment that personality is quite consistent and not varying has been used to explain why human beings have been and remain the dominant species on the planet
B) because such research helps us understand how human beings develop from birth through adulthood
C) because personality trait research has been seen in every subfield of psychology,and evolutionary psychology has adopted the question as a matter of obligation
D) because the variations in personality traits may actually be related to the adaptation and survival of certain species