Which Infant Is Experiencing Assimilation

Multiple Choice

Which infant is experiencing assimilation?

A) Jennifer has previously only played with objects she could put in her mouth so when her parents give her a flexible, plastic book, she immediately puts it in her mouth.
B) Mable turns her head in the direction of her mother's touch when her mother runs her finger down Mable's cheek.
C) Carter makes stepping motions when his parents stand him up on the kitchen table.
D) Nathan has previously only played with objects he could put in his mouth so when his parents give him a soccer ball he first tries to put it in his mouth but then pats it instead.