At Daycare, Nicole and Christine Are Both Fighting Over a Broken

At daycare, Nicole and Christine are both fighting over a broken cookie. They both had cookies of the same size, but Nicole's broke in half and now Christine thinks that Nicole has more than she does. When the daycare provider shows the girls that they both have equal amounts of cookie, Christine calms down as she now understands. Nicole continues to feel superior, having more cookie than Christine. According to Piaget,

A) Nicole has mastered conservation while Christine has not
B) Christine has mastered conservation while Nicole has not
C) Christine has not acquired an understanding of reversibility
D) Nicole is demonstrating object permanence