This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Growth, Development, and Behavior, Subject name: Pediatrics
[{'content': 'A child who can ride a tricycle, uses alternate steps while climbing stairs has attained a development age of: \nSelect and explain. \nA. 2 years, B. 3 years, C. 4 years, D. 5 years', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B. 3 yearsAt 3 years a child will be able to: ride a tricycle, use alternate steps while climbing stairs Shares toys, knows full name and gender', 'role': 'assistant'}]