Which of the following child care policies would be most compatible with the findings of studies of very young children's friendship?

a. When children are old enough to move to the next age grouping in the child care setting, move them with at least one child who is a friend.
b. Children make friends so easily at this age that they won't miss the children from the younger age group; they should be moved up to the next age grouping on their own.
c. True friendship does not exist until children are at least three years old, so no special efforts are required when moving younger children into and out of different groups.
d. The primary relationships that matter for children younger than age three are the relationships with their caregivers and parents, followed by sibling relationships, and then peer relationships. Child care groups should be formed so that they are like small families, diverse in interests, abilities, sex, and age.

A