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 about PPV is, \nSelect and explain. \nA. PPV is proportional to prevalence, B. PPV is Inversely proportional to prevalence, C. PPV has no relation with prevalence, D. PPV doubles with decrease in prevalence', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]