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
Sensitivity is: 
Select and explain. 
A. True positive/True positive + false negative, B. Truerositive/False positive + true negative, C. True negative/True negative + false positive, D. True negative/False negative + true positive
A: True positive/True positive + false negative
Answer: A: True positive/True positive + false negative 
Explanation: True positive/True positive + false negative