This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Health Planning and Management, Subject name: Social & Preventive Medicine
[{'content': 'Beds in CHC: \nSelect and explain. \nA. 20, B. 30, C. 40, D. 60', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (b) 30Ref: K. Park 23rd ed. / 907* PHC level: 4 to 6 bed and staff 15 and 1 MBBS and medical officer* CHC level: 30 beds and 30 staff including 7 doctors MD/MS/OBS/GYNE/ PEDIA/ OPTHA/ANES/PSM* Sub center level: zero bed and 3 staff. MPW (1 male and l female)/ ANM (auxiliary nurse midwife).', 'role': 'assistant'}]