The correct option is A Increasing brain capacity
Binocular vision, smaller jaw, and upright position are the main adaptations that led to the evolution of man from its ancestors. But, during human evolution major and most significant changes occurred in the cranial capacity o man. in living modern man it is about 1450 cc compared to the 500 cc in Australopithecus. Increased cranial capacity accommodates larger brain and forms the basis of the social, cultural and educational evolution of man.