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: Pathology
[{'content': 'Which is not a feature of Downs syndrome \nSelect and explain. \nA. Clinodactyly, B. Pigmented bih marks, C. Hypotonia, D. Respiratory tract Infections', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Pigmented bih marks", 'role': 'assistant'}]