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
A test has 80% sensitivity & 80% specificity. In 1000 population, 100 have disease, Cases missed for diagnosis are 
Select and explain. 
A. 20, B. 70, C. 80, D. 90
B: 70
Answer: B: 70 
Explanation: None