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': "Which is MC genetic cause of mental retardation - \nSelect and explain. \nA. Tuberous sclerosis, B. Cri-du-chat syndrome, C. Fragile-x-syndrome, D. Angel's syndrome", 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Fragile-X-syndromeo Down's syndrome is the most common genetic cause of mental retardation, and fragile-X is second to Down's.Also know o Most common inherited cause of mental retardation is fragile-X-syndrome (because down's syndrome is congenital cause but not inherited).", 'role': 'assistant'}]