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
[{'content': 'Age group for concrete operational stage: \nSelect and explain. \nA. 0-2 yrs, B. 2-6 yrs, C. 7-12 yrs, D. 11-15 yrs', 'role': 'user'}, {'content': 'Answer: C \nExplanation: According to Piaget Cognitive theory, the sequence of development has been categorized into 4 major stages.\n• Sensorimotor stage (0 to 2 yrs)\n• Pre-operational stage (2 to 6 yrs)\n• Concrete operational stage (7 to 12 yrs)\n• Formal operational stage (11 to 15 yrs)', 'role': 'assistant'}]