This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Screening, Subject name: Social & Preventive Medicine
[{'content': 'True positive is indicated by- \nSelect and explain. \nA. Sensitivity, B. Specificity, C. Predictive value, D. Validity', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ref :Parks 23rd edition pg 139 Sensitivity = TP / (TP + FN) Sensitivity is defined as the ability of a test to identify correctly all those who have the disease, that is "true positive".', 'role': 'assistant'}]