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': 'Movement is socio - economic level is \nSelect and explain. \nA. Social equality, B. Social mobility, C. Socio-economic upliftment, D. Social mobilization', 'role': 'user'}, {'content': "Answer: B \nExplanation: Net Reproduction Rate (NRR) is defined as the number of daughters a newborn girl will bear during her life time assuming fixed age-specific fertility and MORTALITY.\nGeneral Fertility Rate (GFR), General Marital fertility Rate (GMFR) don't account for mortality rate.", 'role': 'assistant'}]