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': 'Number of beds in a CHC is: March 2010 \nSelect and explain. \nA. 20, B. 30, C. 40, D. 50', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B: 30', 'role': 'assistant'}]