Which of the Following Illustrates the Concepts of Critical Period

Which of the following illustrates the concepts of critical period or sensitive period?

A) A 3-month-old infant cries when a new babysitter arrives.
B) The period from 6 to 12 months of age is the important time for infants to start eating solid foods.
C) In the months after birth, infants need to experience certain types of stimulation or experiences in order for their nervous systems to develop normally and completely.
D) A 10-month-old infant cries when he is not allowed to throw food on the floor.