This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
According to Piaget's cognitive theory, feature of the concrete operational theory is: 
Select and explain. 
A. Animism and constructivism., B. Egocentrism., C. Symbolic play., D. All of the above.
B: Egocentrism.
Answer: B: Egocentrism. 
Explanation: • Animism and constructivism are seen in preoperational stage.
• Ego-centrism is seen in concrete operation stage. ,
NOTE: Symbolic play is seen in sensorimotor and pre-operational stage.