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': 'If the prevalence of a disease in a population increases,  the predictive value of a positive test - \nSelect and explain. \nA. Decreases, B. Increases, C. Remains constant, D. Becomes compromised', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Effect of prevalence on positive predictive value -\nAs prevalence of disease increases in a population, PPV of screening test increases.\nIt is easy to understand, if the number of patients increases in a population the probability of a positive test will also increases.\nSee following examples', 'role': 'assistant'}]