TOEFL Listening: TPO-TOEFL阅读TPO - H64V2BD639UE4313N$

Why does the author mention "repetitive following movements of the eye"? A. To identify a response that indicates a neonate's perception of a stimulus B. To explain why a neonate is capable of responding to stimuli only through repetitive movements C. To argue that motor activity in a neonate may be random and unrelated to stimuli D. To emphasize that responses to stimuli vary in infants according to age