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: Unknown
[{'content': 'The post-operative quality of life (QOL) scores of 200 prostate cancer patients has a mean of 60 and a standard deviation of 10. How many patients are expected to have a QOL score between 40 and 80? \nSelect and explain. \nA. 190, B. 136, C. 120, D. 140', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The values enclosed in a normal distribution curve are:', 'role': 'assistant'}]