A babysitter cuts a sandwich into three equal pieces, then keeps two and gives one to the child she is caring for. The child is upset that this is unfair, so the babysitter divides the child’s piece into two. Since each of them now has two pieces, the child is content. According to Jean Piaget, this is because the child lacks

a. accommodation.

b. assimilation.

c. formal operational knowledge.

d. sensorimotor ability.

e. conservation.