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 is below the third percentile for height. His growth velocity is normal, but chronologic age is more than skeletal age. The most likely diagnosis is: \nSelect and explain. \nA. Constitutional delay in growth, B. Genetic short stature, C. Primordial dwarfism, D. Hypopituitarism', 'role': 'user'}, {'content': "Answer: A \nExplanation: a. Constitutional delay in growth(Ref: Nelson's 20/e p 2643, Ghai 8/e p 35-37)The child in this Question has: Height below 3rd percentile, i.e., short stature.Normal growth velocity, i.e., normal variant of short stature and Skeletal age is less than chronological age.So, this child has Constitutional delay in growth.", 'role': 'assistant'}]