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: Social & Preventive Medicine
[{'content': 'One standard deviation in normal standard curve includes value- \nSelect and explain. \nA. 50%, B. 68%, C. 95%, D. 100%', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 1 SD includes → 68% of values\n2 SD includes → 95% of values\n3 SD includes → 99.7% of values', 'role': 'assistant'}]