This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Non communicable diseases, Subject name: Social & Preventive Medicine
[{'content': 'Growth rate is calculated by ? \nSelect and explain. \nA. Crude bih rate\\/Crude death rate, B. Net reproduction - Crude death rate, C. Total feility rate - Crude death rate, D. Crude bih rate - Crude death rate', 'role': 'user'}, {'content': "Answer: D \nExplanation: park's textbook of preventive and social medicine 23rd edition. *when crude death rate is subtracted from crude bih rate the net residual is the current annual growth rate.", 'role': 'assistant'}]