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': 'Denominator of positive predictive value is ? \nSelect and explain. \nA. True positve + False positive, B. True positive + False negative, C. False positive + True negative, D. False positive + False negative', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., True positive + False positive", 'role': 'assistant'}]