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': 'One PHC covers how much population in hilly area? \nSelect and explain. \nA. 10000, B. 20000, C. 30000, D. 50000', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., 20000", 'role': 'assistant'}]