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: Psychiatry
[{'content': 'All are feature of Autistic disorder EXCEPT:March 2013 (b) \nSelect and explain. \nA. 75% mentally retarded, B. Usually appears by 2-3 years of age, C. Absent social smile, D. Third person hallucination', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D i.e. Third person hallucinationAutismDifficulty in concentration and communication,Lesion in frontal and temporal lobe and cerebellum,Delayed speech and language development,Problems in forming social relationships in early childhood,Stereotyped movements,Poor speech,Lack of social interaction,', 'role': 'assistant'}]