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 should be present in hilly areas for every: March 2013 (e) \nSelect and explain. \nA. 10,000 people, B. 20,000 people, C. 30,000 people, D. 50,000 people', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B i.e. 20,000 people One PHC is to cover a population of 20, 000 in hilly/ tribal/ difficult areas and 30, 000 in plain areas.', 'role': 'assistant'}]