Daryl has a ball of Silly Putty. His 6-year-old son, John, watches as Daryl flattens the Silly Putty into a thin "pancake." When Daryl asks John if there is now more Silly Putty, John replies, "Yes." Piaget would say that John has:______.
A. not mastered the concept of conservation.
B. demonstrated scaffolding.
C. an understanding of object permanence.
D. demonstrated fast-mapping.