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: Dental
[{'content': 'A test has 80% sensitivity & 80% specificity. In 1000 population, 100 have disease, Cases missed for diagnosis are \nSelect and explain. \nA. 20, B. 70, C. 80, D. 90', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]