This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Demography and family planning, Subject name: Social & Preventive Medicine
[{'content': 'Sex ratio is \nSelect and explain. \nA. 1 male per 1000 females, B. 1000 females for 1000 males, C. Number of female for 1000 males, D. 1000 females per 100000 males', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Sex ratio is defined as the number of females per 1000 males. It is one of the basic demographic characteristic of a population. Reference : Park&;s textbook of preventive and social medicine, 23rd edition, pg no:482', 'role': 'assistant'}]