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': 'If each value of a given group of observations is multiplied by 10, the standard deviation of the resulting observations is \nSelect and explain. \nA. Original std. Deviation / l0, B. Original std. Deviation × 10, C. Original std. Deviation – 10, D. Original std. Deviation it self', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]