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: Pediatrics
[{'content': 'The following are characteristic of autism except – \nSelect and explain. \nA. Onset after 6 years of age, B. Repetitive behaviour, C. Delayed language development, D. Severe deficit in social interaction', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]