Answer:
Calvin's professor can conclude from his question that:
Calvin doesn't know what he's talking about. Although some infants reach these developmental milestones ahead of others, the order is the same for all infants. Option B.
Step-by-step explanation:
According to "Piaget's Stage Theory of Cognitive Development" there are four stages of development in a child": sensorimotor, preoperational, concrete, and formal.
In sensorimotor stage, the infant builds an understanding of himself, interacts with the environment around him and understands how things work.
To conceptualize, he tries physical experiences of things. Then he can think abstractly ans put try to put thinks logically in the concrete stage.
Then finally by formal stage, child can make rational judgments. He or she can give reasoning for his actions. The abstract thinking is more developed. at this stage. This is same for all children. Thus, statement B is most apt from the given options.