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: Social & Preventive Medicine
[{'content': 'Road to health cha was first given by: \nSelect and explain. \nA. John Snow, B. David Morley, C. Dr Francis Peabody, D. Alfred Grojtahn', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The growth or "road to health" cha was first designed by David Morley and later modified by WHO. Growth cha is designed primarily for the longitudinal follow-up. REMEMBER: In Weight -for-age cha, height is not taken into consideration Ref: Park\'s textbook of Preventive and Social Medicine, 21st edition, page-502', 'role': 'assistant'}]