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': 'In severe heat strain the heat stress index (HIS) is ? \nSelect and explain. \nA. 30-Oct, B. 40-60, C. 70-90, D. 100', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is lb' ., 40-60 o HSI 40-60 causes severe heat strain and it is not possible to work comfoably.", 'role': 'assistant'}]