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': 'False regarding thumb sucking is: \nSelect and explain. \nA. Must be treated vigorously in the first year of life, B. It is a sign of insecurity, C. It is a source of pleasure, D. Can lead to malocclusion', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. A. Must be treated vigorously in the first year of lifeThumb sucking is normal in early infancy. It is a source of pleasure in children and is a sign of insecurity. It can lead to malocclusion of teeth, if it persists beyond 5 years. Best policy is to ignore thumb sucking and concentrate on positive aspects of child's behavior. No treatment is required below 5 year of age.", 'role': 'assistant'}]