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
[{'content': 'True positivity is indicated by - \nSelect and explain. \nA. Sensitivity, B. Specificity, C. Predictive value, D. Validity', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]