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
True positive is indicated by- 
Select and explain. 
A. Sensitivity, B. Specificity, C. Predictive value, D. Validity
A: Sensitivity
Answer: A: Sensitivity 
Explanation: 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".