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
Movement is socio - economic level is 
Select and explain. 
A. Social equality, B. Social mobility, C. Socio-economic upliftment, D. Social mobilization
B: Social mobility
Answer: B: Social mobility 
Explanation: 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.
General Fertility Rate (GFR), General Marital fertility Rate (GMFR) don't account for mortality rate.