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: Physiology
[{'content': 'A child is below the third percentile for height. 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: None', 'role': 'assistant'}]