This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Biostatistics, Subject name: Social & Preventive Medicine
[{'content': 'Symmetrical distribution is seen- \nSelect and explain. \nA. Normal standard detion, B. Bimodal distribution, C. Skewed distribution, D. U-distribution', 'role': 'user'}, {'content': 'Answer: B \nExplanation: .', 'role': 'assistant'}]