This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Demography, Subject name: Social & Preventive Medicine
[{'content': 'Midyear population calculated on? \nSelect and explain. \nA. 1st june, B. 30th june, C. 1st july, D. 31st june', 'role': 'user'}, {'content': 'Answer: C \nExplanation: ANSWER: (C) 1st JulyREF: Park 18th ed p.639Mid year population is estimated population on 1st of julyCensus estimation is done at end of first quarter in the first year after a decade (end of march)', 'role': 'assistant'}]